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Tech Zone => Hot Topics => Topic started by: My precious on September 26, 2013, 11:57:57 PM

Title: Updated carb technical spec
Post by: My precious on September 26, 2013, 11:57:57 PM
Does anyone have  the full spreadsheet for the carb specs....?
Found the original on the old site but it appears to be incorrect for the 350B showing only the US/EU baffled filter spec.
As we know, there are many versions of carb settings for the B models. hi-top UK, low-top UK, rest of the world, baffled filter, un-baffled filter and all the undocumented factory upgrades that went on.............. A downloadable Exel spreadsheet for the full RD range would be useful as I have several carb sets I would like to sort, 522 hi-top, 522 low-top, 361 with a choice of either, baffled or un-baffled filters, 2R8 (but possibly the wrong needles)............
Taking in all the above, there seems to be possibly 6 factory set-ups just for the 350B, not just the one posted....
Can we get to the bottom of this and get it in a reference that others can choose exactly what workable set-up they can pick, dependent on the parts they have. I have enough bits to build at least 4 of the 350B variants at one time by chopping and changing. Currently running the hi-top un-baffled version at this time but will be reverting back to hi-top baffled set-up when I go back to standard, just need to track down a baffled filter.................  :-\
Title: Re: Updated carb technical spec
Post by: My precious on September 28, 2013, 12:57:12 AM
My original setup was 521 pipes, 522 high-top carbs, #2.0 slide, 5L3 needle, 105 main jets, 175-06 needle jet, baffled filter, air correction float bowls, 1 3/4 air screw.
Current setup is 521 pipes, 522 high-top carbs, #2.0 slide, 5L3 needle, 140 main jets, 175-06 needle jet, un-baffled filter, air correction float bowls, 1 1/4 air screw due to the F2 tune.
Both viable setups but I have seen/read of a low top version of the 350 and 5I4/2.5 set.
Is this an earlier version fitted to later bikes incorrectly by mistake or previous owners "tinkering" or some sort of bleed-over from other regions OR, imports?
What the end goal is to have a definitive spread sheet that members can refer to for a standard set-up dependent on their engine number, model number and location........... not currently done that I am aware of. Too much talk of needle position, Dale A and Dave Friest mods etc, what is the actual out-of-the-box setting for all the models to avoid the continued questions of what should be in there, and more of "this is what should be in there".............
All a bit grey, conjecture, and this is what I have at the moment. Needs the full details with all relevant info, eg, all of the above including float heights, needle clip position and what actual parts should be fitted to any RD carb as it came out of the factory. Only then, when you have the correct OEM setting, can you tinker with the original. This needs written in stone as to "this is where you start".
Title: Re: Updated carb technical spec
Post by: My precious on September 28, 2013, 07:29:46 PM
I'll confirm that about the needle jet by taking my original 522 carbs apart, they are actually off at the moment, it might be a mistake by me as I have been inside 4 different carbs in the last week............... Was working from memory and I see I got the air screw mixed up between the 2 filter types, but I always get that one wrong  ::)
I have a pair of 361 carbs as well that look original un-tampered....... but, who knows...... Only thing I will be absolutely sure about is my 522's as the only changes made on those were main jet, everything else is as it left the factory.
Will report back tomorrow as I have to go out to a Scout fund raiser and possibly drink beer, have spent all day flat out with the chainsaw.
Title: Re: Updated carb technical spec
Post by: My precious on September 29, 2013, 01:03:39 PM
Errrr, mystery solved, needle jet is 175-08, the 175-06 is in the 2R8 carbs.................. Everything is the same as you have up on the post.

Going to start documenting.
Title: Re: Updated carb technical spec
Post by: My precious on September 29, 2013, 05:28:17 PM
Yes, saw that, haven't come across 5J4 before, might be just a flaw in the stamp mark or a small mark or pit at the bottom of the I.......? Or, a bigger magnifier needed................. I actually use a jewellers 20x magnifier, you know, the one you actually put right up to your eye shaped like a small bucket with a lens on the bottom, works brilliant.

A bit like this one:

http://www.ebay.co.uk/itm/Jewelers-eye-loupe-magnifying-glass-NEW-10X-magnifier-/390659745946?pt=UK_Jewellery_Watches_WatchAccessories_SpareParts_SM&hash=item5af522a89a (http://www.ebay.co.uk/itm/Jewelers-eye-loupe-magnifying-glass-NEW-10X-magnifier-/390659745946?pt=UK_Jewellery_Watches_WatchAccessories_SpareParts_SM&hash=item5af522a89a)
Title: Re: Updated carb technical spec
Post by: My precious on October 02, 2013, 11:08:41 PM
Right, here is the proposed spreadsheet with some of it filled from what I am familiar with and believe to be correct....... possibly...... errrr.

Anyway, as you will see, at present it only contains the UK range with one exception in the Daytona as Dave C has so many of them..............  :D I can add any of the EU/US/CA/AU, etc if given all the necessary data and if I have missed any column titles, let me know.

Will post up new updates when I have entered enough data or am missing data.
Title: Re: Updated carb technical spec
Post by: Colin987 on October 03, 2013, 12:52:00 PM
Interesting - thanks, Stephen!

Colin
Title: Re: Updated carb technical spec
Post by: saddler on October 03, 2013, 03:54:48 PM
nice one Precious  :-\
Title: Re: Updated carb technical spec
Post by: miciver on October 03, 2013, 04:40:31 PM
Thanks Stephen- that is really interesting and of great help, especially as I am working on my 350 restoration currently!

 :)
Title: Re: Updated carb technical spec
Post by: Admin on October 03, 2013, 06:02:52 PM
We got there in the end Stephen  8) 8)
Title: Re: Updated carb technical spec
Post by: My precious on October 03, 2013, 06:21:47 PM
We did indeed........... thanks for persevering with me............  ::)

Anyway, I need input from other members to nail down the rest of the data, I have some but not entirely sure if it is correct.
Point me in the right direction to find where it is hiding or just post it up here and I will fill it in.
Title: Re: Updated carb technical spec
Post by: Colin987 on October 03, 2013, 07:10:22 PM
Interesting to see the B model float height is 16mm as a pose to the other round tank models 15mm (... if you find that sort of thing interesting, of course ;D).

I guess that would cause them to run a bit leaner; or am I wrong??

Has anyone fiddled about with float heights - does a 1 or 2 mm difference have much effect?

Colin
Title: Re: Updated carb technical spec
Post by: My precious on October 03, 2013, 07:31:39 PM
The B model had a different carb from the rest of the "round tank" series and the 2 main differences were the slides and the link to the airbox, I'm not sure if the air corrector jets were different, this is the only bit of info I am not sure of..... Both the above mods changed the way the air was delivered to the venturi and internals and must have required a "tweak" to the float height to bring things back to standard factory settings.
That would cut the fuel off 1mm sooner than the earlier carbs, but, honestly, not sure if it would make that much difference as you are allowed +/- 1mm and theoretically still be in spec.............  :-\
Title: Re: Updated carb technical spec
Post by: saddler on October 03, 2013, 09:54:51 PM
We did indeed........... thanks for persevering with me............  ::)

Anyway, I need input from other members to nail down the rest of the data, I have some but not entirely sure if it is correct.
Point me in the right direction to find where it is hiding or just post it up here and I will fill it in.


have you come across this link to the 'old' forum Stephen ?  ???

www.aircooledrdclub.com/smf/index.php?topic=39201.0 (http://www.aircooledrdclub.com/smf/index.php?topic=39201.0)
Title: Re: Updated carb technical spec
Post by: My precious on October 03, 2013, 10:19:25 PM
Yes, I did look at that but cannot trust whats there as the 350B one's which I do know, are wrong............
Wrong needle, wrong slide, wrong air screw setting, wrong float height.......
The 250B one's are totally mad, same issues as above but also wrong carb model and float height given as 23mm....  :o
Similar problems with the 250A, carb type, needle, air screw, float height.
I think " this is a combination of the EU and UK with some other stuff that's of unknown origin", so I can't trust the rest as being correct as there are so many mistakes.
What I need is the actual data from members that have un-tampered carbs and can report what is reality.
Title: Re: Updated carb technical spec
Post by: saddler on October 03, 2013, 11:14:45 PM
 :D I hope 400C is correct mate I've recently set mine up using that info  ::)
Title: Re: Updated carb technical spec
Post by: My precious on October 03, 2013, 11:24:34 PM
Hmmmmm..... wouldn't bet the farm on that being correct either..............  ::)
So many people with carb problems........... think I've got to the bottom of it. The wrong info is out there, a bast@rdization of more than one area and some "made-up" stuff it seems.
Title: Re: Updated carb technical spec
Post by: My precious on October 04, 2013, 12:20:27 AM
Well............ we know where some of those crap parts come from.........  >:(
If you are not in a hurry, OEM stuff is still to be got in the US, so, I pre-empt this by purchasing certain items in advance.
You may have seen my recent purchase of a pair of original Dykes 360 pistons for $29 each (£18). Sort of a real piss-take by JT's looking nearly £100 for one piston  :o
We can sort this bit anyway if I can get the necessary info back from members.
Title: Re: Updated carb technical spec
Post by: My precious on October 07, 2013, 12:59:56 AM
What a nightmare this is turning out to be.............. After EXTENSIVE research, on-line, current posts in the new forum, tech data in the old forum, studying the Yamaha workshop manuals, the supplementary manuals and referring to the following carbs I actually have, 361-G1, 361-G3, 522-00 (x2), 2R8-00), a certain amount of "Poirot" detective stuff later..... I have updated the A/B and 2R8/9 data.
It seems that the carb suffix code is vitally important, eg, what comes after 361 or 2R8 on the choke body. Seems that there is a unique set of carbs produced for the UK that runs with baffled filters. Basically, if you have a UK bike, with the original carbs, you have to have smaller jets, a 2.0 slide and a short needle. If you change to an un-baffled filter, it is NOT a simple case of re-jetting, you have to change the slide and needle as well (needle in the case of the earlier 250/350, slide only in the later bikes). In the same light, you can't just "bung on" any carb bits you happen to have lying around, there may be a different set of air corrector jets in the different carbs, I haven't got to the bottom of whether this the case yet.
Early (low) suffix numbers are for the "rest of the world" and any superseded numbers are for the UK............ except the 522-00, as it was possibly specifically produced for the UK and the rest had the 361.............. maybe.................

This may or may not be definitive, unless someone has actual bikes with un-tampered carbs that are genuinely UK or rest of world and can genuinely and categorically state that "this is what is in mine out of the factory"....? I can only genuinely state with hand on heart that the 361-G3 and 522-00 are as-is.....................

Latest update here:

Title: Re: Updated carb technical spec
Post by: JRD on October 07, 2013, 06:43:09 AM
Sounds like you have your work cut out.

I picked up what I hope are unmolested carbs from a 350 here in Oz from the local wrecker.

FYI

Carb ID is 360-02 Hi Tops
2.5 Slide
5I4 Needle Clip in 3rd groove
175 type 0-8 Needle Jet
25 Pilot with number on head (slot end)
Main Jet 170
Float arm "A"
Air Screw 1 3/4
Title: Re: Updated carb technical spec
Post by: My precious on October 07, 2013, 06:08:22 PM
Would agree with that, the rest looks about right but the main jet is not............... now......... another carb rears it's head  :-\
360-02.
What's it off I ask? 350A or 350B, obviously different set for AU/NZ, hi-top would suggest B model but the 360-02 number suggests the non-letter or A model. Do the float bowls have the large air correction tube barbs to the airbox and the brass ball blocking the airway at "6 o'clock" in the intake?
Any of the other 350's with either slide/needle combo have the needle in the 4 groove, with the 250 having it in the 3rd, but, you have the long type 2.5 slide normally used in the US.
What's in the bike you've got now?
Title: Re: Updated carb technical spec
Post by: Colin987 on October 07, 2013, 06:41:57 PM
Hi Stephen,

of the six carbs fitted to my German 250A's (model 352), five are stamped 361G1, and the other (right hand) one is stamped 360G1, for some obscure reason!

Colin
Title: Re: Updated carb technical spec
Post by: My precious on October 07, 2013, 07:44:02 PM
OK, thanks, from that is seems that the non-letter and A models were the same in both UK and EU and only went all complicated from the B...............  ::)
Bit of a mystery with the 360-G1, where does that come from? Obviously, the right carb is different in that it has no choke but I've never saw 2 different code ones on the same bike as standard  :-\

Will update that unless someone knows different.............. ?
Title: Re: Updated carb technical spec
Post by: Colin987 on October 07, 2013, 07:50:19 PM
Bit of a mystery with the 360-G1, where does that come from? Obviously, the right carb is different in that it has no choke but I've never saw 2 different code ones on the same bike as standard  :-\

Don't do any updating with my data.....   I think all my bikes have had a dubious tampered-with history!  :o

Colin
Title: Re: Updated carb technical spec
Post by: My precious on October 07, 2013, 08:09:54 PM
It's fairly conclusive that 3 of your 352 model bikes have 361-G1 (well, almost), and as the UK 361 model also has this setup, it looks like there has been a simple run-through of the carb up to the baffled filter A model. But, it is curious though that all of your 352's are running a carb, which, effectively is off a later model.................... how does that work  :-\
Title: Re: Updated carb technical spec
Post by: Colin987 on October 07, 2013, 08:19:31 PM
Just had a closer look... with a magnifying glass! :-[

My "odd" carb would appear to be a modified 360 - the "0" has been crossed-out and re-stamped "1".

[attachimg=1]

(Hell; this must be boring for other readers!)

Colin
Title: Re: Updated carb technical spec
Post by: My precious on October 07, 2013, 08:40:33 PM
Ah..... a factory upgrade.........  :D Crossover model probably when the model this went on finished and they used up old stock. Hey! maybe it is a valuable collectors item worth a fortune, like stamps that had mistakes that got out into the wild....  :o
Yes, must be like paint drying for some, but, a lot of members will benefit.
Still want to find out what a 360 is off, orrrrrrrrrrr is it a mistake altogether and there was never a 360 carb?
Title: Re: Updated carb technical spec
Post by: JRD on October 07, 2013, 09:21:46 PM
I'll double check the brbs tonight (i'm at work checking this posting)the box at the wreckers said RD350.
Its sounding like a definitive spreadhseet would be a god send!!
Will slip in a photo but  I believe there is a ball in the carb mouth at 6 o'clock
as I did notice one of them has a gouge mark - just wonder if someone had had a go
at getting them out or maybe it was just dropped at some point.

Can you clarify the needle clip positionsyou quote 1 is at the top of the needle 5 at the bottom - so position 4 is
one notch richer than centre?

The bike originally came with a 250 tuned top end but was a 350 bottom end - not the norm.
The carbs were low tops and I didn't take a lot of notice of their settings at first as they
went on my 250LC race bike until recently. I think I have the settings written down in the book.

the otherset of Hi tops came from a mate and have had the Dave Freist mod and were originally set up for
a 400 race bike but I'll check the body stampings.
Title: Re: Updated carb technical spec
Post by: My precious on October 07, 2013, 10:14:57 PM
I actually have in my possession a pair of 2R8 carbs that are in the spec on the sheet that came off a mate's 250E when he totally modded it after a crash and went full cafe racer with different carbs, that's how I ended up with them.
From that and my research I assumed that there was a baffled version for the 400 as the jetting of the 2R8 suggested that there was when you compare it with the un-baffled 115/145 version, but, no confirmation. So, what is the 2R8-10, 95 main, 5L1, 175-06, 2.0 slide, 22.5 pilot off............?

Wasn't able to get confirmation on the filter type on the C/D so that's why it was left un-finished, along with the rest of the jetting data. I'll take that out bit out and hunt down the rest, unless you know it and I can fill all that gap in?

I couldn't track down definitive written proof that A's had a hi-top set-up, any that I have seen have been the black carb body but with the alu finished low-tops. Hence the entry in the EU spec for the A model until definitive data has been received. If you know the full spec and that the A's were all fitted with them I can update that as well.

The 522-00 carb was put down as being UK only as it is un-documented and the only time I have heard mention of it is on UK bikes, never anywhere else. From my research, the 5L3 was also in the 250D so that is probably how he was able to get one.

We have a bit to go yet on this..... project.
Title: Re: Updated carb technical spec
Post by: My precious on October 07, 2013, 11:08:55 PM
Yes the 2R8-10 carbs are definitely jetted for baffled filter and off a UK bike.

Was inputting that data and spotted you have the same 5L3 needle for both, from 2 different sources I have got 5L1 in the 400C/D, but only confirmed for EU and Canada....... did the UK run the same needle?
Title: Re: Updated carb technical spec
Post by: My precious on October 07, 2013, 11:20:49 PM
Indeed............ I have to triple check everything.
As for the C/D, are the UK setups the same as EU?
As I have found (and have) a UK 2R8 carb different from the EU, I am not sure if EU settings can be just transferred over, as the B settings are different as well?
Noticed the the later float heights are +/- 2.5mm, is it just me or is that not a bit excessive and, er, wrong when the early models are all +/- 1mm.
Title: Re: Updated carb technical spec
Post by: My precious on October 07, 2013, 11:44:25 PM
Who is to say the bike wasn't "hot", came from a dealer who wasn't Yamaha and somewhat dubious but it was 30 years ago....? If this was a German set-up only I'll put it in as we do have members.....
I've been cross-referencing the same sources possibly but backing it up with parts and info I have and searching the forum, jeez... it's feckin' time consuming.
I'll put in what I have done tonight and what you have sourced and put it up in about half an hour but there are still gaps and we will need some input from members to confirm some stuff and fill in some of the final gaps......

The 351/2 with 360/1 parts is a mystery, I can only think that they were already producing the new versions of the parts from external suppliers but was not economically viable to change frame and engine runs at the time.

Looked at the US/CAN/AU/NZ issues and will probably wait for members to come back with definitive data as this has been hard enough to sort. Started a couple of entries but when New South Wales has its own carb.............. I went "feck that"
Title: Re: Updated carb technical spec
Post by: My precious on October 07, 2013, 11:58:23 PM
I'll put up what I have shortly and it can be tweaked from there as I have killed too many brain cells for today.................
I know there is the UK/EU/US 1A0/1A1/1A2/1A3/2R8/9 GREY area and will be easier to fix when it is up and can be read against all the others.
Title: Re: Updated carb technical spec
Post by: My precious on October 08, 2013, 12:18:29 AM


Can you clarify the needle clip positionsyou quote 1 is at the top of the needle 5 at the bottom - so position 4 is
one notch richer than centre?


1 is at the top and will give a weak mixture, subsequently 5 is at the bottom and will be a rich mix.
Title: Re: Updated carb technical spec
Post by: My precious on October 08, 2013, 01:01:04 AM
Latest version for update................

Title: Re: Updated carb technical spec
Post by: JRD on October 09, 2013, 04:46:22 AM
Here is a photo of the 02 carb
(http://i48.photobucket.com/albums/f202/Jools58/RD350A/IMG_0728_zpse77b1a19.jpg) (http://s48.photobucket.com/user/Jools58/media/RD350A/IMG_0728_zpse77b1a19.jpg.html)
The ball is not at 6 O'clock but in the hole to the left.

how about his for an unmolested NOS carb? pity they only had the one  :(
(http://i48.photobucket.com/albums/f202/Jools58/RD350A/IMG_0729_zpsdf24424a.jpg) (http://s48.photobucket.com/user/Jools58/media/RD350A/IMG_0729_zpsdf24424a.jpg.html)

Its a 360 A3 type and a quick initial look confirmed 2.5 slide and 5I4 needle
Shiny !!
(http://i48.photobucket.com/albums/f202/Jools58/RD350A/IMG_0732_zps6e6e1445.jpg) (http://s48.photobucket.com/user/Jools58/media/RD350A/IMG_0732_zps6e6e1445.jpg.html)
Title: Re: Updated carb technical spec
Post by: My precious on October 09, 2013, 09:05:31 PM
Hi Guys, had to take yesterday off as brain was fried..............  ::)
So, back on the horse as it were and back to the grindstone.
Just made Fajitas for the first time for tea, I'm more of a meat, potatoes and 3 veg + gravy and have all of that down to a Tee, first time for a wok as well, 53 and I'm still learning shit.................  :D
Right, 360-A3........... that's one of those carbs specifically made for the Wagga Wagga region of NSW...?
Actually, that's the first low-top I've seen with a black top  :-\ AND..... the that's the first hi-top I've seen without air correction float bowls........... jeez, what a nightmare, you Aussies have a lot to answer for.............  :D
Excel...... here I come.
Title: Re: Updated carb technical spec
Post by: My precious on October 09, 2013, 10:56:23 PM
OK, some things to throw out there.....
522-00 I am convinced is UK only and only found on the B models (unless our German members can tell us what was on the 1976 RD350 there.......?)
I was not aware that the 250A came bare finish, but, that said, they were sort of different carbs with different main jet and pilot jet, so would have had a different suffix code, which incidentally I haven't been able to get yet for the 350A baffled and un-baffled.
Any other "rest of World" black carb was a 361.
I have only found evidence of 360 carbs in AU/NZ.
I am giving C/D/E/F etc as VM28SS as the earlier VM28SC did not have the slide height inspection plug but did have independent floats. This makes it a different carb from C with the synchro window and "paired" floats. Can't see the "SS" as special, only a next gen carb and that changed from the C on to the F. Only grey area is the 2VO..... was this the same unit effectively as the C?

The DS7 and R5 needle jets. What jet is 0-0.......? They are all 175-something........ Also the 2V0, needle jet makes no sense also given as 0-0.

As for the long slide thing, if you look at the 2 of them stripped out in front of you, the high-top is way more engineered with quite a few extra parts and more metal involved, more expensive and therefore doomed due to cost cutting.
Title: Re: Updated carb technical spec
Post by: My precious on October 10, 2013, 12:11:28 AM
Latest version:

Title: Re: Updated carb technical spec
Post by: JRD on October 10, 2013, 12:22:30 AM
The NOS black low top above (360-A3) was sourced from Canada

Do you think that the carb part numbers might reveal some alignment with your findings?

Its quite possible that the part number suffix relates to any internal differences for locality.

this NOS carb has a -02-00 suffix. a search through all the parts books might be revealing ?
Title: Re: Updated carb technical spec
Post by: My precious on October 10, 2013, 01:01:37 AM
Yes, I stated from my findings earlier in this thread that the suffix number is very important.
It gives the version and "country" (and in Oz, a specific region.......... there is even one for high altitude regions, suffix -50).
Standard -00 is for the country it was originally destined for, subsequently, each re-jetting for another region changed the code. The code does not tell you which country, only that it is a "variant". You have to know the carb model and the suffix to which it applies and has no specific formulae to determine the region.
As the 522-00 is found on UK "B" models, this states that this carb was designed to be for UK use primarily. I am not aware that there was a 522-10 so at this time, the 522 is a UK only set-up.
In that same light, the 2R8-00 was the carb designed for the 2R8 250E. All 250E's around the world have the 2R8-00 carb as there was no variant........... except for Belgium, which had a baffled filter and therefore a re-jetted carb to suit, 2R8-10, why, I ask, is Belgium the only country in the world that had to have a baffled filter on a 250E.....? In that vein, the 522-00 baffled filter hi-top was only for the UK......? Bugger................

I'm missing the 350 non-letter and the 350A code so that may be 360 as you state. Thing is, the 250A came in 2 flavours.... 361-G1 non-baffled and 361-G3 baffled filter. So, we have to find out the 2 suffixes for the 350A versions as well or the info is not complete/incorrect.
We need 350/350A owners to tell us what the codes are................

I have just noticed a potential mistake............. I have the 350B and 250B down as 522-00, but, this theoretically incorrect as the 522-00 is only for the 350B, looking at the rest of the data and the fact that the 250B has different jetting, and needle clip position, the 250B should actually be 521-00, OR, 522-10...............  :-\
Again, I need the owner of a genuine original UK 250B to supply the correct info. The engine I got for my 250B rolling chassis is a 250A so I can't help myself. I will be converting this to full 250B spec on the rebuild though.
Title: Re: Updated carb technical spec
Post by: My precious on October 10, 2013, 08:14:07 PM
Whilst I'm waiting for Microsoft to stop tinkering with my Office 2013.................... yes I tried to open it and was told it was busy because Microsoft were "updating, making changes and removing programs" and it would be "available shortly".  :-\ Didn't even know they had snuck in the back door.

Anyway, shall discuss the points raised.
Although I have never heard of seen a number being "tampered" with by a manufacturer, I can't see an individual going to the bother of doing this themselves, like, have you seen the size of the numbers? I need a x10 jewellers loupe to see mine. They look very authentic and match perfectly in size, must have been an "end of run" stock use.

I have the entire guts of a 400C in stock so should be able to sort something out there by swapping the entire thing onto the 250A shafts so I can retain the original clutch and sprocket.

Ah......... I'm allowed to use office again, will post up the latest in a while and will try to re-size things to fit it on to one A3 making it easier to view.

Title: Re: Updated carb technical spec
Post by: My precious on October 10, 2013, 08:29:05 PM
Did the EU have the 522 and 521 models or did they stick with the 361 and 360. Might explain why 521 silencers are as rare as unicorn horn and the only baffles you can get are 360's ?
Title: Re: Updated carb technical spec
Post by: My precious on October 10, 2013, 09:42:00 PM
Latest version now with formatting to make it easier to view..............  :)

Title: Re: Updated carb technical spec
Post by: My precious on October 10, 2013, 09:59:08 PM
Yes, 1A0 baffles fit grand, you just can't buy pattern ones, only 360 type, only NOS or used if you are lucky to find a pair not broken off at the perforated tube.
Title: Re: Updated carb technical spec
Post by: JRD on October 10, 2013, 10:07:04 PM
Something else to consider that may have been overlooked -

A very high percentage of bikes have probably been restored, some as basket cases and there is no guarantee that the carbs were included and as a consequence from another model.
When you say genuine - have you owned this bike from day 1 or obtained it complete where it was blatantly obvious that nothing had been changed

This could lead to some of the head scratching that you are experiencing. As I found, the last pair I bought were in a box at the wreckers labelled RD350. As they are high top assuming they have been identified correctly, from what I read here they should be from a 350B.

BUT I also bought a pair last year - Hi tops which 1A0 carbs. Its threads like this that help identify what I have or Haven't got.

As for the suffix I mentioned previously, I was referring to the actual carb part number in the parts book ie
360-14101-02-00 is from the Canadian NOS carb 360-A3.
Title: Re: Updated carb technical spec
Post by: My precious on October 10, 2013, 10:52:07 PM
The originality issue is why we have embarked on this epic task, most will not realise the amount of time involved in the background researching and cross-referencing this data.

Hi-tops were only fitted to late A's or B's.
Only the UK B had the 2.0 slide 5L3 needle, the rest had 2.5 slide 5I4 needle. The odd-ball is the hi-top you have with no float bowl air correction tubes..............  :-\ up until now, I thought that hi-top and link to airbox was a given.................

the 1A0 with a hi-top is a mix and match by someone tinkering to try to resolve something or the only way they could get the parts they needed to get a running carb set. From what I have so far, the 1A0 was for the 250C UK (not confirmed yet if this was also fitted to US/CAN/AU/NZ) but not on the EU bikes as they went straight to 1A2 carbs.
In theory, if you fitted a long 2.5 slide, retained the 5L3 needle from the original, move the clip to 2, put in a 115 main jet, you have converted it to hi-top, unfortunately you now have the problem of the air corrector jet and air screw setting. I don't have the black hi-top air jet sizes yet, but at 1.0, I suspect they are larger than the early carbs so the air screw will have to be in further than standard spec and unknown issues (if any).............  :-\ So very close but one thing not right and it only takes one thing................ But, should work up on a 250C, not so if working back to put this on a 250B.
Title: Re: Updated carb technical spec
Post by: My precious on October 10, 2013, 11:47:26 PM
Nah...... the 1.0 air jet I was referring to was on the 2R8 carb........ possibly wasn't worded in the right order.
So, all the air jets up to B were 0.5? Did this include the DS7 and R5....?
Title: Re: Updated carb technical spec
Post by: My precious on October 11, 2013, 12:33:16 AM
Indeed.......... I'm still working on it, my OCD sees the gaps in the info and it's like nails down a blackboard.......... All the cells will have to be filled before I will be able to "leave it".
Probably 99.5% of members thought there was only one carb for one model, how wrong they were. The constant requests for carb data prompted me to do this (with loads of input from you) and I also expected more input than the couple of members who did step up...... so thanks to JRD and Colin for their input. Maybe it was too techy or no-one wants to go out into a cold garage to look at their carbs.....  ::)
It's still incomplete so I need input from members to fill the gaps remaining.
I've learned a bit but no more than I already knew on the UK B model, it's the rest that is a nightmare and the tampering, bodges, imports, pattern part suppliers have muddied the water terribly.
Need more data guys......................
Title: Re: Updated carb technical spec
Post by: Colin987 on October 11, 2013, 05:20:15 AM
Air jets on my 250A certainly look to be 0.5mm... unless my middle-aged eyes deceive me!

Colin
Title: Re: Updated carb technical spec
Post by: RDnuts on October 11, 2013, 08:08:13 AM
seems to be a lot of too and throwing going on regarding carbs and also seems a lot of worrying , basically the reason for the carb change to the 522 carb is one of air correction jet position on the 360/1 carbs whether high top or not the pilot jet gets its air from the mouth of the carb this caused problems as fuel that got spat back towards the filter would fill up the air jet and upset the mixture, also fuel would go stale in this area and eventually block up the air jet, to ovecome this the 522 carbs feeds its air to the pilot jet from a small drilling through the carb body and into the float bowl and exits via the rubber tube into the air box , this prevented the problem above ,  basically all of the vm series carbs for rds onwards use this system,  reason for the " slide and needle change was probably a form of restriction as the b models on paper tended to be slower than previous models read  previous post i put up regarding the difference, the longer 521 pipes come about for noise reasons , baffled filters come along first on the 74 model year again for noise induction reasons as customers complained about it this required a main jet change , high top carbs again came along in 1974 along with taller slides reason for this was to prevent slides from sticking as they incorporate a weight in the slide as previous models did not, this allowed the slides to shut better as it also loaded the spring better allowing for a more positive return of the throttle it also helped the cable run as it has a better curve and routing , the earlier carbs tops basically the cable went from near horizontal to near vertical and used to kink the cable after a period of time and allowed water to enter the carbs it is strange as to why they went back to the low top carbs on the c model onwards which suffers from the same problem as the earlier 360/361 low top carbs,  i suppose this could be that the throttle tube on later models is locked into position on the frame , all uk b models and europe had 522 carbs and the 2 slide set up, german models along with belgium were restricted to 28bhp this was done with a longer down pipe, and 0-6 spray tube i have however come across a few italian b models that have had 360/361 carbs fitted along with 360 silencers and the 2.5 slide set up these have had a very odd mixture of a 521 engine and a 351 frame on the prefix and have the the same number suffix  a real odd ball , there is a update that shows the b model part changes for carbs in a yamaha parts news to which one day ill post up dealers where supposed to update their parts books few ever did this shows the carb body's slides, needles, main jets, air tubes and pilot jets  a later update shows mk2 variation of the 522 carb which used the same idle screw and air screw set up as the later carbs with an o ring and has a blank casting set in the body as if it should have had a screw to undo to set up the slides as per the later carbs a sort of inbetween carb ,  these have 522- 01 on the body to denote a design change every thing else remains identical , basically you can use any vm28 rd carb on any model rd the key is to get the jetting correct and along with the correct spray tube etc along with cables etc, these days you can expect to see plenty of mongrels out there with some right lash ups if possible always try and get the right carbs and set up for your models saves a lot of messing about
Title: Re: Updated carb technical spec
Post by: RDnuts on October 11, 2013, 03:14:30 PM
oops slight error i did mention air jet and somehow mentioned pilot in the same sentence,slap on the wrist, anyhow i have run both set ups on the same bike the 2 slides and needle set up appears to run a bit richer than the 2.5 slides etc born out of the 2 slide would run richer by way of the cut out and the 5l3 needle being longer and has a different taper this in effect would slow the bike down on full throttle also in my test my bike would not redline in sixth and struggled to get to the its top speed, try and find the post i put up as i dont want to repeat the results here, I have yet to repeat the tests on a 350, i also have the green sheets for the b models which show the same data you have (which is wrong) even yamaha got things incorrect this is why they had YAMAHA PARTS NEWS TO inform dealers etc of any production changes i have had several german spec bs pass my hands and they too have had the 2 slides and 5l3 needles top speed for the b models show 147kph, where as earlier models show 160kph the 147 closer to the truth , the rd 250b was still the quickest 250 out there at the time but no longer the fastest , would still rather have the yam over the suzook anyday and even the claims made by suzuki where a bit wild, the needle does not clear the spay tube on full throttle other wise there would be a risk of the needle not going back in the tube when you close the throttle, now that would be good fun , for originality all my b models have the correct carbs and slides and needles ,but i prefer the 2,5 slide and needle set up ill dig out the yamaha parts new sometime this week end and try and get it posted ,no doubt this will still keep the fires burning
Title: Re: Updated carb technical spec
Post by: My precious on October 11, 2013, 06:27:07 PM
Right, suffering from number overload, I'm going to take a different tack and deal with one model at a time.
Lets concentrate on the 250/350B.
For the UK 250B, I have no data on the carb type but have all the settings filled in. As it has different jetting etc it will have a different number.
For the UK 350B, I have the 522-00 and all the data filled in.
For the EU 250B, I have it down as a 361-92 with the normal Euro 5I4 needle 2.5 slide as that was documented.
For the EU 350B, I have no data on the carb type but have all the settings filled in. As it has different jetting etc it will have a different number.
Now we find that there is documentation that the Euro B's had the same as UK B's.

Soooooooo......... What I need to know:
What's the carb model in the UK 250B? 361-92 or some version of the 522-00? If it is a 522, the suffix has to be different as some of the internals are different from the 350.
I had found info the the EU 350B had the normal euro setup - 5I4 etc. Could it be that the 250 had the 361-92 and the 350 had the 522-00? What complicates this theory is that the 361-92 is the 5I4/2.5 set and the 522-00 is the 5L3/2.0 set.
What I have found is that a 250 and a 350 or 400 will NOT have the same carb model number as they are different settings.
Title: Re: Updated carb technical spec
Post by: My precious on October 11, 2013, 10:07:30 PM
I'm not convinced there is a 521 model carb........... Why? Because the 522-00 is fitted to the 521 bike (350B), so, It would be really weird if a 521-00 was fitted to the 522 (250B) bike, like, the wrong way round  :-\ :-\
I have had little or no evidence of what a 360-xx carb is fitted to either, other than the odd-ball 360-A3, all black low-top NOS carb JRD got from Canada.
As yet, I haven't tracked down any data or evidence of what bikes a 360-xx carb was on apart from maybe..... the US 350B had a 360-60. If it was, then there was a 360-00/10/20/30/40/50 (although it did come up earlier that -50 was used to denote a high altitude version). I still have all the 350's (apart from the B's) to do....................
Title: Re: Updated carb technical spec
Post by: JRD on October 12, 2013, 05:50:04 AM
The carbs that came with this bike I'm restoring, and there is no guarantee of authenticity as it was a dogs breakfast,
the LH Carb has a 3 on the top with an A beneath it. The RH carb is 360 -02
 (http://i48.photobucket.com/albums/f202/Jools58/RD350A/350RH_zps28dc8096.jpg) (http://s48.photobucket.com/user/Jools58/media/RD350A/350RH_zps28dc8096.jpg.html)

(http://i48.photobucket.com/albums/f202/Jools58/RD350A/350LH_zps49127d41.jpg) (http://s48.photobucket.com/user/Jools58/media/RD350A/350LH_zps49127d41.jpg.html)
The bike, although a 350 frame and cases had a tuned 250 top end and TZ crankshaft.
Title: Re: Updated carb technical spec
Post by: 5port on October 12, 2013, 07:27:45 PM
Stephen, try to get the "cycleserv" servicing manual. There is quite a bit about the 250/350 in the specs there.
Title: Re: Updated carb technical spec
Post by: Kingsley Davies on October 12, 2013, 08:55:49 PM
I've got a set of HT carbs that came with an Italian import 350 motor and they have the prefix 360-02 that you recently mentioned!

514-4 needle
2.5 SLIDE
140MJ
25 PILOT
175-08 JET HOLDER

I've also got another set of HT's with prefix 360-92 that were on a yds7 hybrid I bought that had an RD350 motor fitted.

details same as 360-02!

I have a 250D which I have recently fitted a 350 top end to, I have left the 1A2 carbs on for now as I have been told by a

couple of reliable sources that they run ok like that - it doesn't! lol!

So I'm having a bit tweak with the 1A2's for now, anyone any tips?

Cheers!
Title: Re: Updated carb technical spec
Post by: RDnuts on October 13, 2013, 12:04:45 AM
as i have mentioned before in another post there are no521 carbs  all early 522 carbs are 522-00 later type have 522-01 these apply to both the 250 and 350 , , they must have changed the production method at the factory to make sure carbs had the right jets in for a 250 or 350 easy on earlier carbs as they were marked 360=350 and 361=250 on the 522 carbs they either fitted correct jets as the carbs when fitted with the engine or had a sticker or other id to show what jets were fitted , i have also a pair of carbs marked 360 xx if you look more closely the x are overstamped over g1 so who knows what thats all about , all of the uk and european bs that have come to me or i have bought, 250/250 some german and dutch models with a french one in for good measure have all had 522 carbs fitted and the 2 slides 5l3 set up the only exception i have seen is a couple of italian bs that have the 360/361 2.5 and needle set on them this maybe because of the climate, which as captain kirk would have said we are not alone bones, seems that they are not uk specific, you cant always go by any clymer or cycleserv haynes manuals to give you the correct data, you cant even rely on yamaha to get it right , i have been going through a few yamaha parts news today to try and find the bit about  b model updates only another 300 to go through  ::) they do make comical reading some of the advice that they gave to the dealers on how to deal with problems is a right ol laugh  :D
Title: Re: Updated carb technical spec
Post by: Kingsley Davies on October 13, 2013, 10:34:50 AM
Doing good Brian, you?

Thanks for the advice, sounds sensible!

How you doing Kingsley?

The only real difference with the 1A2's and the 350 carbs is the air jet is 1.0mm and the air filter/box is different. I think you would be better of sticking with the 1A2's and their own airbox as the 361's or 522's are matched to their airbox.

Sticking with the 250D unbaffled filter a simple change of main jet to around 135/140 and lifting the needle a notch or so should be all thats needed. The standard 115 will be dangerously lean. Timing left at 2.0mm
Title: Re: Updated carb technical spec
Post by: Guri131 on October 13, 2013, 03:14:04 PM
Brilliant thread we got going here. A  :-* to all the contributors.
Title: Re: Updated carb technical spec
Post by: My precious on October 13, 2013, 09:17:40 PM
OK, will put this up against what I have already and see how it fits, another anomoly on the B's there, 2 different carbs 522-00 but different internals............. totally against all other scenarios and only on the B  ::)

Don't have 351/2 carbs on the list, only 361 versions, you might have looked at the wrong column with the bike models in it.
Title: Re: Updated carb technical spec
Post by: RDnuts on October 13, 2013, 09:59:22 PM
there are no 351/2 carbs
Title: Re: Updated carb technical spec
Post by: My precious on October 13, 2013, 10:20:39 PM
The 360-02 carb might be the elusive missing model for all the early 350 models.
I had worked out all the jetting and internals for the 350/350A that it should be from the surrounding data but had no carb model number.......... it fits the jigsaw.
Title: Re: Updated carb technical spec
Post by: My precious on October 14, 2013, 12:12:13 AM
I've got a set of HT carbs that came with an Italian import 350 motor and they have the prefix 360-02 that you recently mentioned!

514-4 needle
2.5 SLIDE
140MJ
25 PILOT
175-08 JET HOLDER

I've also got another set of HT's with prefix 360-92 that were on a yds7 hybrid I bought that had an RD350 motor fitted.

details same as 360-02!

I have a 250D which I have recently fitted a 350 top end to, I have left the 1A2 carbs on for now as I have been told by a

couple of reliable sources that they run ok like that - it doesn't! lol!

So I'm having a bit tweak with the 1A2's for now, anyone any tips?

Cheers!

From what I have discovered they look the same but the differences were hidden from view.
The 361-92 was a re-jetted 361-G1 for a baffled filter and for 250's.....the 360-02 was the 350 jetted version of the 361-G1......... The 360-92 you mention have had the jets and needle clip changed from a 250 to suit a 350, that's why they are the same. Effectively it's the same carb otherwise, just a re-jetted 250 one............. clear as mud.
Title: Re: Updated carb technical spec
Post by: My precious on October 14, 2013, 12:45:32 AM
Latest version for checking:

Title: Re: Updated carb technical spec
Post by: 5port on October 14, 2013, 01:59:59 PM
360 is the generic model code that covers all the early RD250/350. ;)
Title: Re: Updated carb technical spec
Post by: Kingsley Davies on October 14, 2013, 02:12:08 PM
Good you mentioned about stamping over because when I was reading numbers on carbs I could see evidence of this!
Glad someone knows whats going on! lol

as i have mentioned before in another post there are no521 carbs  all early 522 carbs are 522-00 later type have 522-01 these apply to both the 250 and 350 , , they must have changed the production method at the factory to make sure carbs had the right jets in for a 250 or 350 easy on earlier carbs as they were marked 360=350 and 361=250 on the 522 carbs they either fitted correct jets as the carbs when fitted with the engine or had a sticker or other id to show what jets were fitted , i have also a pair of carbs marked 360 xx if you look more closely the x are overstamped over g1 so who knows what thats all about , all of the uk and european bs that have come to me or i have bought, 250/250 some german and dutch models with a french one in for good measure have all had 522 carbs fitted and the 2 slides 5l3 set up the only exception i have seen is a couple of italian bs that have the 360/361 2.5 and needle set on them this maybe because of the climate, which as captain kirk would have said we are not alone bones, seems that they are not uk specific, you cant always go by any clymer or cycleserv haynes manuals to give you the correct data, you cant even rely on yamaha to get it right , i have been going through a few yamaha parts news today to try and find the bit about  b model updates only another 300 to go through  ::) they do make comical reading some of the advice that they gave to the dealers on how to deal with problems is a right ol laugh  :D
Title: Re: Updated carb technical spec
Post by: Yammy 38 on October 14, 2013, 10:27:07 PM
Hi Stephen, really good list, a vast improvement on what was listed on the old tech pages and definitely needed doing.  I am no RD expert (I have some YR5 info) I will leave the RD stuff to the big hitters on here but I have a few comments if you wish to include them. 

My YR5C is a 1972 model and I have 3 carbs marked 278 - A2
UK main jet is 110 and the pilot is 40.  Taken from genuine Yamaha manual and these sizes were fitted to all carbs I have seen for YR5, also the Air correction jet size should be 2.5 mm (not 0.5mm)  I measured it on all my 278 carbs.  Don,t forget the Piston port YR5 & DS7 had Spray Tube Needle Jets not Primary type. The Needle Jet number is 169 0.0


Also on the RD side I do not want to add a  column to you chart uneccessarily but don't forget the Float needles!!   I only recently found out the brass float body have different hole sizes in the base.  I know the RD400 needs 2.5 mm and the YR5 has 2.0 mm fitted.  I nearly fitted the wrong ones from a kit I purchased, not sure of the consequences but it might be critical for fuel flow when giving it some welly.
Here are the two I have showing different sizes.
Great work on the chart - I hope we can all fully complete it and make available on this site for future referance.
[attachimg=1]
 
 
Title: Re: Updated carb technical spec
Post by: My precious on October 14, 2013, 10:35:49 PM

My 361-92 are on my UK 74 pre A and never have has had a baffled filter?? The bike was pretty original when I got it about ten years ago and doubt the carbs were changed, but you never know? That's the trouble with this :-\

Will try and check back where I got that data for the 361-92 as it is an odd-ball...........  :-\ In this current list, it only appears on the UK 250A and was an all-black hi-top in standard early/EU/US jetting.
I have found that on the late 250A they did a transitional change from the original setttings and ended up with a carb that was half 361 and half 522 using the hi-top and baffled jetting from the 522-01, but, retaining the venturi air correction and 2.5 slide from the 361-G1, making a completely new carb.... When the B came out it went full airbox correction, 2.0 slides etc.
Title: Re: Updated carb technical spec
Post by: My precious on October 14, 2013, 10:39:41 PM
Thanks Jamie, I've been waiting for someone to put up the necessary early stuff.............
As for adding in columns, it's in Excel so easy to do. Might put it in if it fits without pushing me out of the 2 A3 pages I have now.
Title: Re: Updated carb technical spec
Post by: dandywarhol on October 14, 2013, 10:59:32 PM
Could someone please show me the difference between baffled and non baffled filters? (you can tell I'm baffled!)

I've a recently imported Swedish late '74 RD250A (352) with 36I - 92 on the choke body and 2.5 slide. I haven't checked the other details yet.

I felt the bike was running weak in mid range and really only got going with 3/4 to full throttle. Turns out the floats were set 22mm from the gasket face/8mm from the mail jet tower. i'm guessing someone has set the floats to the wrong spec. Reset to 15mm and running like I remember my old 350B ran in early 80s (but with a bit less power  ;))
Title: Re: Updated carb technical spec
Post by: My precious on October 14, 2013, 11:09:44 PM
OW31 and dandywarhol............ what jetting is in your 361-92 carbs?

Haven't got a picture (sure others have) but, by description, the baffled filter has 2 tapered tubes inside the filter and one end blanked off. If you do take one out and re-fit it, make sure you put it back in the right way round or you cut off the air supply to the carbs and it will not start, let alone run............ got that t-shirt.... ::)
Title: Re: Updated carb technical spec
Post by: Dunx675 on October 14, 2013, 11:34:47 PM
I think that the 1976 RD250C carbs should be stamped 1A2-00 (although you're right, the generic model prefix is 1A0).

This came from a discussion at Webbs Yamaha on Saturday, when I was discussing carb overhauls with the Steve there.  The parts book does list the complete carb as 1A2-14101-00. (And for the RD400C as 1A3-14101-00)

I'm standing by to be corrected by those who know better!

Dunx
Title: Re: Updated carb technical spec
Post by: My precious on October 15, 2013, 12:21:19 AM
From what I've found, the part number and model code stamped do not necessarily go hand in hand.
I have found that the 1A2 is fitted to the EU 250C and D, but............ there are differences right through the model range that are not model and date locked, with one carb running through several models in one country, but 3 different carbs for the same period in another, and a completely different carb in another area. Haven't got hard evidence yet of the actual code on the UK 250C but the part number is not a guide to the stamping and therefore jetting setup. If owners of original UK 250C's can confirm what they actually have it can easily be updated, the code can be seen on the right carb without removing it with a magnifier.
So far I have found 4 different carbs for the 250A.............  :-\
I get parts for my 350B which start 278 (R5) or 360 (350) when mine is a 521............... and I have fitted a couple of 1A0 bits  :o
Title: Re: Updated carb technical spec
Post by: Colin987 on October 15, 2013, 05:35:46 AM
A couple of pictures to clarify:

5L3 needle is actually a couple of mm's shorter than the 5I4, and is thinner in the same relative positions, measured from the needle grooves.

[attachimg=1]

Unbaffled and baffled filters.

[attachimg=2]

Colin
Title: Re: Updated carb technical spec
Post by: Colin987 on October 15, 2013, 05:44:29 AM
And for those who aren't aware:

Lo-top 2.5 slide left; hi-top 2.0 slide right.

[attachimg=1]

Colin
Title: Re: Updated carb technical spec
Post by: dandywarhol on October 15, 2013, 12:17:38 PM
Excellent info for us noobies Colin - thanks. I guess the baffle is to reduce noise but does it affect performance?
Title: Re: Updated carb technical spec
Post by: RDnuts on October 15, 2013, 09:08:40 PM
yamaha part numbers are like different hats to fit different heads, you have yamaha numbers and ibm numbers for good measure,   413 prefix comes into play, on some part numbers you, will see allsorts of part number prefixes when you look through a parts book, different parts of the world again use different prefixes that denote the part is intended for that area only carbs generally have 360/1 a1 g1 91 92 on them and on the data sheets it will what it should have and whats allowable in brackets, all the 522 carbs i have seen either have 522 00 or 522 01 on them there will allways be oddballs that turn up from time to time and as can be expected to find an unmolested bike now is getting harder  and some fiddling hands may have altered summut
Title: Re: Updated carb technical spec
Post by: My precious on October 15, 2013, 10:39:50 PM
Yammy 38: That R5C spec you have is R5B spec in my Genuine Yamaha Manual and is matched in the Clymer data. But mine is Yamaha US data, never seen a genuine UK only service manual.

The R5C spec in mine is: MJ 120, Needle 5DP7-4, Pilot #30, Needle Jet 0-4, #2.0 slide, air screw 1-1/4 and as you say Float Valve Seat 2.0 rather than the RD's 2.5.

Is 72 a bit early for a R5C? Mine was a Feb 73?

My 250 LT 360-92 carbs are as follows: MJ 120, Needle Jet 0-8, Needle 514-3, Pilot jet #25, Slide #2.5

I originally had that spec for the R5C but changed it so that needs clarified............
I haven't got a 360-92 carb in the sheet, only a 361-92. Which one is a 250 LT.... ?
Those settings look like a 250A low-top un-baffled setup, but........ with the 25 pilot jet from the 350A/B  :-\ another variant raises its head.
Title: Re: Updated carb technical spec
Post by: Yammy 38 on October 15, 2013, 10:53:34 PM
Hi OW31,
You could be right about my R5 being a R5B model - mine was registered in Sept 1971 which is early for the C.  My crib sheet only shows the R5C differences as a different battery and different wattage lights fitted and for some reason listed as 1 kg heavier. All other specifications are the same. :-\
My manual I believe is genuine UK - it is the green cover one with Matsui Machinery Sales (UK) Ltd on the rear cover at 117 - 119   Denmark Road London.

It does show 110 mains and 40 pilots for the UK bikes with Needle jet 0.0
The UK bikes did have a smaller jets.  :)
[attachimg=1]
Title: Re: Updated carb technical spec
Post by: Yammy 38 on October 15, 2013, 10:55:08 PM
OW31,
Sorry - other pictures should have been added - I clicked too soon.

Yammy38
[attachimg=1][attachimg=2]
Title: Re: Updated carb technical spec
Post by: My precious on October 15, 2013, 11:08:52 PM
Some concerns have been raised about this and will cause people to start searching for a specific carb so their bike is "right" which in some cases, will be nigh on impossible as some carbs will be extremely rare or tampered with.
The model codes are pre-assembled "factory Mikuni" but, in most cases are just a standard body (of which there are only about 6 bodies due to the fixed air jet and 3 float bowls I can see.......  :o ) and just have a myriad of variants for the model they are fitted to.
This is not the point, this is not necessarily a "bean counter/RD police" exercise. For the purists, this will send a warm glow through their loins, for the member who has just put a 350B top end on their 250C, this will show them what mods they have to make to their carb to make it work and whether or not they can actually make that conversion. It will give them an option of possibly 3 or 4 other carbs they can fit and make the necessary changes so that the jetting and internals are correct for what they have.
Thus, it is vital we put together the definitive guide to the STANDARD for every model so others can sort their standard/conversion/bodged bike..... tuning is another thing altogether and we won't be going into that here.

BTW, with regard to the 350B/250C conversion, it doesn't look like you can convert a 250C carb to 350B spec as the fixed air corrrection jet in the 250C is 1.0mm where the 350B is 0.5mm. Also they have a totally different float bowl, floats and float height and a different air filter box. The main jet, slide and needle clip position could be changed but the other stuff negates the mod.
From the spreadsheet, the 350B carb would be correct, but alternatively the 250B or late model 250A with jetting changes would also suffice with the minimum of parts required. But, how the later airbox would interact with the B carb conversion is unknown.
Title: Re: Updated carb technical spec
Post by: My precious on October 16, 2013, 08:32:48 PM
Right......... more conflicting info...........  :-\
The 361-92 data I have is for a baffled, 95 main, 5I4, etc........ hi-top for the 250A late model.
The 360-92 data I have now been presented with should be the 350 version of this, BUT..... I have now been given data that it has a 120 main from one source which makes it an un-baffled 250 carb and with venturi air correction from another, surly this will be an un-baffled unit with 140 jetting and low-top? neither of them make sense, one should be the re-jet of the other in the same spec.........?
Title: Re: Updated carb technical spec
Post by: 5port on October 20, 2013, 10:03:45 PM
Just a note that all is not lost on the fixed air corrector jet side of things.  You can drill and tap the body for the screw-in air corrector jets.  It is a 3mm drill out the fixed corrector for tapping a short 4mm thread.  Covered in the Dale Alexander mod. ;)
Title: Re: Updated carb technical spec
Post by: dandywarhol on October 21, 2013, 06:59:45 PM
Right......... more conflicting info...........  :-\
The 361-92 data I have is for a baffled, 95 main, 5I4, etc........ hi-top for the 250A late model.
The 360-92 data I have now been presented with should be the 350 version of this, BUT..... I have now been given data that it has a 120 main from one source which makes it an un-baffled 250 carb and with venturi air correction from another, surly this will be an un-baffled unit with 140 jetting and low-top? neither of them make sense, one should be the re-jet of the other in the same spec.........?

I hope to get mine 356-92s dismantled at the weekend to further confuse you MP  8)
Title: Re: Updated carb technical spec
Post by: RDnuts on October 22, 2013, 08:30:04 AM
Was thinking Stephen, I know it's dangerous :D

I am not convinced the A's that had high tops were 522's I think they might have still been 360's without the air box air correction. Where's Rdnuts when you need him :-\ He probably has 10 of them!! One reason being you could get a high top upgrade kit for the earlier versions. Was to prevent slide sticking due to the longer stronger spring. Funny how it only lasted a little more than one model!

Also my faded memory tells me that 250 low top carbs were bare alloy and 350 low tops were always black. At least in the UK. In the US they might have all been black, I have bought a few sets of 360's from the states and they have all been black.
i have been feeding stephen with loads of info so he can update his sheet i dont think we will ever be able to complete the definitive of variations of the carb types as different markets have different numbers etc but basically the carbbodys are the same with small differences in them mainly main jets slides needles pilot jets etc  and how the air correction circuit works , jetting is married to what type of filter your running irrespective  of slide and needle combinations  what we really need is members from different parts of the globe to add what they have on their bikes that have been untouched to get the base data correct i have info from usa/canada uk/europe asia and australia/new zealand but some areas are missing, climate and other factors determine what may be fitted inside the carbs at the factory , like most carbs the changeable elements of the carb allow for such variations in different climates running conditions etc, so long as some basic settings and info are to hand i dont think you can go far wrong its then up to the owner to play around as much as they dare
Title: Re: Updated carb technical spec
Post by: My precious on October 22, 2013, 08:19:15 PM
Took a bit of a holiday from this project myself, time to get back on the horse..............
Title: Re: Updated carb technical spec
Post by: My precious on October 22, 2013, 11:19:47 PM
I needed to print this out so I can work on it "old fashion"............. have spent a good part of the night working out why my wireless printer was now just "a printer".............  ::) Now fixed but the night is lost............... after some investigation, it may well be something the missus did a few nights ago when she had some issues with a USB key and re-arranged some leads.
Had to start from scratch with the setup so it could "see" the wireless network again. Try again tomorrow............
Title: Re: Updated carb technical spec
Post by: My precious on October 29, 2013, 10:14:45 PM
Still working on this........ took some time off from it but now collating info from PM's, posts and external sources for another update shortly. Have it printed out........ feck, it is big and hand filling in info to cross reference it old style............
Title: Re: Updated carb technical spec
Post by: My precious on November 14, 2013, 02:58:15 PM
OK guys........... this hasn't gone away you know.   ::)
So, latest version here, re-formatted to fit on 2 A4 pages and some more stuff filled in but I have essentially reached the limit of what I know and have been able to dig up reliably.
There are still quite a few gaps in the info, especially on the right hand sheet and I need your help to fill this in. Some stuff at the bottom as well to do and a bit on the R5/DS7.
It's actually not far away from completion so need a final push to bring it home.

Title: Re: Updated carb technical spec
Post by: 5port on November 14, 2013, 04:44:22 PM
OOhhhhh, me eyes are goin funny :D.

Bit of a mix-up on the third note for 360/361 carbs, "30 and 25 air corrector"?
Title: Re: Updated carb technical spec
Post by: My precious on November 14, 2013, 05:40:27 PM
What bit is wrong..?
All pre B RD250's are fittted with a 361 carb and a 30 corrector, all 350's are fitted with a 360 carb and a 25 corrector.  :-\
Title: Re: Updated carb technical spec
Post by: 5port on November 14, 2013, 07:32:15 PM
What bit is wrong..?
All pre B RD250's are fittted with a 361 carb and a 30 corrector, all 350's are fitted with a 360 carb and a 25 corrector.  :-\
Well, air corrector jets are usually refered to as say 0.5.  Pilot jets are #25 or #30 for instance.  Is that what you meant? 
Title: Re: Updated carb technical spec
Post by: russiansteel on November 14, 2013, 08:10:12 PM
What bit is wrong..?
All pre B RD250's are fittted with a 361 carb and a 30 corrector, all 350's are fitted with a 360 carb and a 25 corrector.  :-\
Well, air corrector jets are usually refered to as say 0.5.  Pilot jets are #25 or #30 for instance.  Is that what you meant?
and they seem to be 0.5 for both 360 & 361 carbs, meaning the third note is really not applicable.
Title: Re: Updated carb technical spec
Post by: My precious on November 14, 2013, 10:06:04 PM
Yes, got it now............ suffering from number and word blindness there and got mixed up between the pilot jets and air correction and I do know what I'm doing, was getting late last night when I was doing it.............  ::)
Will fix it now.......................
Title: Re: Updated carb technical spec
Post by: My precious on November 14, 2013, 10:42:07 PM
OK, think that is sorted........... what about the rest now?

I can do this in A3 to go on one sheet but most people do not have an A3 printer.

Latest version:

Title: Re: Updated carb technical spec
Post by: stephen bailey on November 16, 2013, 07:47:43 AM
this is a great help my precious !!!! many thanks steve notts
Title: Re: Updated carb technical spec
Post by: miciver on December 16, 2013, 08:16:30 PM
OK, think that is sorted........... what about the rest now?

I can do this in A3 to go on one sheet but most people do not have an A3 printer.

Latest version:

Stephen- just checking this is the very latest one?

I am going to strip my 350 carbs this week to see what is inside them before going any further with my resto so would just like to check.

Many thanks for all the hard work on this.  8)
Title: Re: Updated carb technical spec
Post by: My precious on December 16, 2013, 08:28:03 PM
I'm still tinkering with it on and off, will do a bit more tidying up and put the latest up later this evening...
Title: Re: Updated carb technical spec
Post by: miciver on December 16, 2013, 08:38:43 PM
Great thanks  ;)
Title: Re: Updated carb technical spec
Post by: My precious on December 16, 2013, 10:56:38 PM
Latest version.............. On 2x A4's.

There are still gaps in it so need more help to fill it in as I have exhausted my own knowledge and available data that I can find. Someone mentioned the Cycleserve manual, but I have not been able to track this down.

Title: Re: Updated carb technical spec
Post by: My precious on December 16, 2013, 11:25:11 PM
Haven't got the Clymer manual either....

Yes, 350's 1 3/4 on the unbaffled filter versions, 1 1/4 on the baffled B only.

I had come across the R5C "variant" but had no confirmation if it was so and if it was US, EU or UK....?

As for missing stuff, easier to look at the PDF instead of me putting it all up here, the missing info is left blank.
Title: Re: Updated carb technical spec
Post by: My precious on December 17, 2013, 12:11:32 AM
Yes, I came across info that the A could come with 3 versions of carb setup.
Most common is the black low-top, un-baffled, 2.5 slide.
Very late A's had Hi-tops that normally would have a baffled filter but as you know, UK data is virtually non-existant, even though we know these setups existed.
So, what I have done is put in the 3 possible setups that an A can run with:
1: low-top un-baffled.
2: low-top baffled.
3: hi-top baffled.
The hi-top did not come standard with an un-baffled filter, always baffled, so anyone with 140 main in a 350A, fittted with a hi-top has had it changed by someone.
None of the A's had the airbox tube correction to my knowledge but that did not effect the jetting across the baffled filter versions.
360/1 is a part code correct, another one slipped through the net, that's why I keep putting this up for scrutiny.
That should be 351/2.
I was contacted by a member that they had a R5C with the same settings as a R5B so I am confused as to what goes in there and there is the possibility that there is a country version here.? Will have to go through all my messages to find out where that came from........  ::)
Title: Re: Updated carb technical spec
Post by: My precious on December 17, 2013, 01:11:11 AM
Latest version with latest corrections............

Among other stuff still needed, ones with most info missing is DS7, 250E (US) and Daytona.

Title: Re: Updated carb technical spec
Post by: miciver on December 17, 2013, 07:33:51 AM
Thanks Stephen, and also everyone else who contributed to this- looks like a minefield.

 ;)
Title: Re: Updated carb technical spec
Post by: My precious on December 17, 2013, 08:18:46 PM
It won't be handed over until it's finished.
Still need 250E (US) if you have that.
Title: Re: Updated carb technical spec
Post by: My precious on December 17, 2013, 09:02:18 PM
Ah.... I thought they went to the D but did not know they dropped it altogether that early at the 352. I knew there was no 250F.

More correction needed, well actually, one line to take out in reality.......
Title: Re: Updated carb technical spec
Post by: My precious on December 17, 2013, 09:59:38 PM
Haven't come across a Canadian 250C/D/E as yet.
I do have data for a AU/NZ 250F with 2R8 engine and 2V3 carbs so it seems they got the same as us possibly....? but with their own different carbs and jetting.
Title: Re: Updated carb technical spec
Post by: mervin on December 17, 2013, 09:59:51 PM
Stephen , pdf of clymer manual, if it does not work let me know , choose slow download fast one tries to charge you

http://www.fileswap.com/dl/VmuebLAi/D250-400_1965-1978_Repair_Manual_%281%29.pdf (http://www.fileswap.com/dl/VmuebLAi/D250-400_1965-1978_Repair_Manual_%281%29.pdf)
Title: Re: Updated carb technical spec
Post by: My precious on December 17, 2013, 10:56:17 PM
Thanks Merv, got that....... eventually  ::)

Thanks OW, plenty to browse through there.
Title: Re: Updated carb technical spec
Post by: mervin on December 18, 2013, 11:28:04 AM
Interesting i have a paper version of the clymer,  but never comapared them
Title: Re: Updated carb technical spec
Post by: mervin on December 18, 2013, 12:59:29 PM
Mine is the same as that one , the 1978 version with the uk supplement at the back 
Title: Re: Updated carb technical spec
Post by: mervin on August 27, 2015, 11:50:36 PM
Ok i have just found this and moved it OW31 is the topic you where reffering to ?
Title: Re: Updated carb technical spec
Post by: Angel Grinder on November 05, 2018, 11:45:48 AM
I've got a carb that's not on your list yet Stephen; it's a 360 92 (I notice you've got the 361 92 spec on there). I've only got the one, which I picked up from Kempton Park ealier this year.

So I guess this is the late UK 350A? A black Hi-top. Do you have the spec for this or would you like me to tell you what's in there?

Obviously, I have no way of knowing if the internals are original but it's all there except the needle.
Title: Re: Updated carb technical spec
Post by: My precious on November 05, 2018, 07:22:56 PM
I have an update I'm working on for the data sheet, I've got my hands on a lot of carbs recently and have made a few additions and some changes.
The 360 92 I've got is black hi top, air correction intake in the venturi, 105 main, 5I4 needle with clip on 4th down, 2.5 slide, 1750-8 needle jet, 25 pilot jet, 2.5 fuel valve, but it would be good if you can see what's in yours and if its the same. From that jetting it's a late 350A but, for a baffled filter version so UK model most likely.
Title: Re: Updated carb technical spec
Post by: Motty on November 05, 2018, 07:29:37 PM


I have an update I'm working on for the data sheet
Hello Stephen, it's good to see your post

Your carb data sheet has been referenced now and again, thank you for keeping it up to date

Sent from my Moto E (4) Plus using Tapatalk

Title: Re: Updated carb technical spec
Post by: stukey on November 05, 2018, 10:08:54 PM
Now and then, my shitty shit is handy ;)
Title: Re: Updated carb technical spec
Post by: 5port on November 07, 2018, 08:06:43 AM
I have an update I'm working on for the data sheet, I've got my hands on a lot of carbs recently and have made a few additions and some changes.

Good to see you are working on that Stephen.  Your carb data sheet is a great resource!  Thanks

5port
Title: Re: Updated carb technical spec
Post by: iranana on November 15, 2018, 01:34:21 AM
Not sure if this is valuable info or not, but I have an NZ/AU 1978 250E that came with 2V3 carbs. I've always assumed they were the original ones, I see the AU/NZ 250F uses them also.
Title: Re: Updated carb technical spec
Post by: ozmadman on November 15, 2018, 04:47:20 PM
I have an update I'm working on for the data sheet, I've got my hands on a lot of carbs recently and have made a few additions and some changes.

Good to see you are working on that Stephen.  Your carb data sheet is a great resource!  Thanks

5port
Here..here!!!  many thanks Stephen, all your hard work is a gold mine of information. And.... good to see you back on the forum  ;) ;)
Title: Re: Updated carb technical spec
Post by: My precious on November 15, 2018, 11:51:31 PM
Thanks and thank you to iranana for the info, I'll add it to the next update, I've got a good amount of info lately, Neil and Peter have sent me a load of carbs and I continue to learn new stuff, especially when they can tell me exactly where the carbs came from and I can tell if they have ever been opened or tampered with. I've had 5 new air cooled versions and LC / 31K carbs too.
Title: Re: Updated carb technical spec
Post by: mervin on October 07, 2019, 08:31:25 PM
latest update from Stephen

[attachurl=1] 

A tidier version

[attachurl=2]
Title: Re: Updated carb technical spec
Post by: stukey on October 07, 2019, 09:44:47 PM
The amount of time and effort stephen has put in to this data sheet is imeasurable and will help a lot of people with clear  precise information for years to come, going forward. To have been just a small part in this is an honour and getting  restored carbs back in better than new condition is a real win for me. Well done mate :) :) :)
Title: Re: Updated carb technical spec
Post by: Motty on October 07, 2019, 11:10:35 PM
latest update from Stephen

(Attachment Link)
Thank you for the update Stephen

Sent from my Moto E (4) Plus using Tapatalk

Title: Re: Updated carb technical spec
Post by: Kickstart on October 16, 2019, 11:34:21 PM
yea, thanks Stephen for taking the time to help others. great info
Title: Re: Updated carb technical spec
Post by: RDnuts on November 01, 2019, 08:02:30 PM
the chart is showing the r5 float valve as being 4, this is not correct it should read 2 cheers now
Title: Re: Updated carb technical spec
Post by: My precious on November 01, 2019, 08:23:12 PM
I had 3 pairs of R5 carbs and they all had 4.0 in them.....?
Title: Re: Updated carb technical spec
Post by: RDnuts on November 01, 2019, 08:43:00 PM
yes but not standard part number tells you the size ends in 20 meaning 2 many carbs get altered from previous  owners number 4 i would have thought would let in loads of fuel probably used for racing sprinting etc have a few 278 carbs here all showing 2s  parts books show number 2, genuine service manual tells you also, trouble is you cant take for what you see in a carb as correct , i have just bought from japan an rx350 pro basically an r5with a disc brake at the front a very rare find indeed watch this space as it get put back to its former glory carbs showing #2 float valves
Title: Re: Updated carb technical spec
Post by: My precious on November 01, 2019, 08:54:48 PM
The Yamaha tech sheets cannot be taken as the Bible, there were loads of mistakes, dealer updates that weren't available to the public, undocumented part changes, transition parts that had a later casting but with earlier parts in it, bits that were identical on the outside but different on the inside..... I no longer trust anything Yamaha put on paper and go with taking apart dozens of components and building a database from that, the switches are no different, lots of changes in the later coffin tank models that are internal, needs loads of reference parts to figure it all out. And I know what I'm doing.....
Title: Re: Updated carb technical spec
Post by: RDnuts on November 01, 2019, 09:17:15 PM
whos disputing you know what your doing ?  but your wrong if your using the findings of old carbs to put in stone for others to follow ,loads of mistakes happened at yamaha thats why they issue memos to dealers and workshops to correct any,  if you think about it in an engineers prospective why would you use #4 float valves when all the rest use #2 or 2.5 the 3 carbs you have probably came from the same source were they on a bike? in a bucket of carbs? in bits , etc you know the score have you ever owned an r5? i know the time it takes to compile a list and in the fog of loads of data its easy to make a mistake there are other errors in there but after your reaction to this post i wont bother pointing them out we all know what we know and sometimes best kept that way , I merely pointed out an error and then get chewed about it, correlating data is no easy task but verifying its accuracy if even harder anon . ps id just like to add with the new modern fuels and next year 10% ethanol coming sadly all this data will become irrelevant i can see hard times ahead for all of us with these machines we gonna have to work hard to keep our machines on the road
Title: Re: Updated carb technical spec
Post by: My precious on November 01, 2019, 09:27:14 PM
One pair came off a bike, 2 didn't, one of those had never been been apart, you can tell if a carb has been apart when you have serviced over 100 Rd carbs, and I have a mate who has a low miles R5 with known history I fettle.... Its all about hands on stuff which you also have but thats what has come out here. And I am an engineer......
Title: Re: Updated carb technical spec
Post by: RDnuts on November 01, 2019, 10:12:45 PM
your mate with the r5 whats sitting in the carbs? ah yes the old im an engineer so i must be right argument, I worked at Ford motor company 30 years making transit vans I lost count of the engineers coming and telling us this should go this way and that i had a simple message  for them come on the line and show us how it is done none ever did seeing a drawing and assembling something are two different things at 30 vans an hour the operator knew how to do it an engineer thought he did, now im not knocking you in any shape or form but sometimes engineers see things in a different way sometimes overthinking things clever at somethings dunce at other tasks , it also depends on what type of engineer your ace at ,ive met many different fields of engineers as you cant be a jack of all the best ones i come across are those that got there hands dirty who had a sense of mechanical ability and knew how to use a spanner and had the knowledge not only from a book but real world learning id like to think your in that zone, learning comes from errors we all make them its how we learn from them, how we might think what we saw might be wrong, i have some brand new 522 carbs here in their boxes also some 2r9s  would i just fit them hoping all is correct in there ,no of course not ill have to take them apart just to check , i know that main jets are often wrong in new carbs so the first port of call , and to find a carb that is not new thats never ever been apart well your one lucky fellow as i never have , lost count how many i have done but must be well over 1000 and counting , please tell me if the carb in question was painted?  again dont take things the wrong way , and for the record did i not supply some of your data a long time back ? pretty certain i did
Title: Re: Updated carb technical spec
Post by: My precious on November 01, 2019, 10:34:58 PM
I stand by my findings....
Title: Re: Updated carb technical spec
Post by: RDnuts on November 01, 2019, 10:53:04 PM
i stand by facts and insider knowledge gained over 45 years and even then i dont profess to know it all and i never will but im over your neck of the woods early next year id still buy you a beer and talk shop
Title: Re: Updated carb technical spec
Post by: twostrokelooney on November 02, 2019, 09:44:04 AM
I have an update I'm working on for the data sheet, I've got my hands on a lot of carbs recently and have made a few additions and some changes.

Good to see you are working on that Stephen.  Your carb data sheet is a great resource!  Thanks

5port
Here..here!!!  many thanks Stephen, all your hard work is a gold mine of information. And.... good to see you back on the forum  ;) ;)

Couldn't agree more with the sentiments above and good to see you out and about again Stephen...... :)
Title: Re: Updated carb technical spec
Post by: stukey on November 02, 2019, 04:14:13 PM
Dave. Maybe it would be more constructive to supply all of your data and cumulative knowlage to stephen direct, so as he can collate and cross-referance with the data he already has. That way we will all benifit :)
Title: Re: Updated carb technical spec
Post by: My precious on November 02, 2019, 04:18:10 PM
i stand by facts and insider knowledge gained over 45 years and even then i dont profess to know it all and i never will but im over your neck of the woods early next year id still buy you a beer and talk shop

Aye, could happen, where are you heading to...?
Title: Re: Updated carb technical spec
Post by: RDnuts on November 02, 2019, 10:53:09 PM
well i did that and got shot down on the r5 fuel valve i thought that was just correcting an error i spotted ,did not want it to turn in to the great debate have supplied data in the past but to be honest its ok knowing the then data but its all changed with the crap fuel we have to use now and is now redundant spoke to a few of the race guys at donnington who do tz and the like they have had to change all there known previous data and started with clean sheets to keep their strokers at the peak they have to use pump fuel now and its changed the world for them sadly after quite a few blow ups but have let me in on a few of their secrets which have applied to two of my riders still have a bit more playing around to do but i think im getting there the first holed piston will tell me i went to far
Title: Re: Updated carb technical spec
Post by: stukey on November 03, 2019, 07:24:04 AM
If you are experimenting with fueling and ignition Dave and are in danger or holing a piston. It would be prudent to use our forged pistons.They are tougher and stand up to a lot more abuse than cast ones.We supply to a lot of the top race guys ;) I don't think Stephen was criticising your information Dave.He was just relating his information according to his findings. this is in a very linear engineers way, as opposed to a laymans point of view
Title: Re: Updated carb technical spec
Post by: RDnuts on November 03, 2019, 10:26:58 PM
Stephen ill be in a place near Keady  Armagh in march
Title: Re: Updated carb technical spec
Post by: RDnuts on November 03, 2019, 11:33:43 PM
If you are experimenting with fueling and ignition Dave and are in danger or holing a piston. It would be prudent to use our forged pistons.They are tougher and stand up to a lot more abuse than cast ones.We supply to a lot of the top race guys ;) I don't think Stephen was criticising your information Dave.He was just relating his information according to his findings. this is in a very linear engineers way, as opposed to a laymans point of view
[/ha ha im not an engineer but know just a little bit on how to play around with ignition and fuelling , trick is not to do both at the same time id never use a forged pistons on a road bike the race guys i spoke to have done the hard work for me basic stuff was to up main jet and take ignition any where between 1.7 btdc and 1.9 btdc , holing pistons aint my game but tell tell sounds let you know just before this happens so if your astute at knowing then it can be avoided and plug chops let you know if bits of piston are being lost ,last holed piston i did was on my dt250 on the iom blating my way at a dizzy 80mph on the way to peel for breakfast metallic  rattle then pop timing was spot on carb settings spot on ,id just filled up with iom fuel blamed that as fixed piston it never blew again no rattle at 80 back home no holed piston wierd
 quote]
Title: Re: Updated carb technical spec
Post by: My precious on November 04, 2019, 12:11:18 AM
Stephen ill be in a place near Keady  Armagh in march

Keady is about half an hour away from me.... Distance is irrelevant in Ireland, its all done on how much time is involved.