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Aircooled RD Tech Help 250cc and Above / Re: Running on one cylinder…
« Last post by Whitey on Today at 12:30:52 AM »
New coils from Yambits fitted and all good so far, smoking now gone from RH pipe and firing well on both cylinders.

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Aircooled RD Tech Help 200cc and Below / Re: RD200 DX replacement pistons
« Last post by DeepThought on October 01, 2022, 10:49:21 PM »
Hi the 1E8 piston runs rectangular type rings and the 397 runs a dykes top ring. you can run the 397 pistons with the dykes(L) ring but they are actually for the earlier 397 model.
Ah- that now makes sense. For sake of replacing like for like, I’ll continue to search for the correct original part. From the pictures on Yambits, their offering look like the rectangular type so may consider those if no luck. Thanks Phil!
Aircooled RD Tech Help 250cc and Above / Re: Joining Air Boxes on RD250D/350
« Last post by Whitey on October 01, 2022, 10:40:32 PM »
Just looking at Carb settings info on here, which is very useful…

350 with un-baffled air filter is #140 main and #105 with baffled air filter.
As 250D runs an un-baffled filter, I guess  #135 isn’t far off the mark.

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Aircooled RD Tech Help 250cc and Above / Re: Joining Air Boxes on RD250D/350
« Last post by Whitey on October 01, 2022, 10:30:15 PM »
Going back to the "air duct/pipe/joint" between the boxes. Yes, with a 350 conversion I would change the 250 part with 3-tubes, to a 400 square tube or just a soft rubber seal between the two boxes.  On my 350 road conversion, I have a 400 square "tube" in the standard airbox with a 250 type unbaffled filter and it runs best on carbs set-up with the jetting for a UK RD350B.   :)

Hi, sorry for the late addition to this thread but I’m on the road at last and just sorting out my jetting.

Quick re-cap Carbs are 1A2, engine and Airbox are RD250D, early 350 barrels and heads.

The bike is running suprising well! Pilot Circuit is fairly strong and pulls well up to 6k at 1/4 throttle - after which it still pulls but lacks some power.

Current Settings:
27.5 pilot jet
135 main
Std 5L3 Needle

Running pre-mix

I did expect that it might not be getting enough air flow through the std air box and I think that’s what’s holding back the top end. I was going to mod the Airbox to either no joining pipe or a modded one as per the 400 - which I have a great set of drawings for thanks to another member ( Andy)

[mention]5port [/mention]
You mentioned that you had best results jetted as per a 350b - di you remember if that included using a 2.0 cutaway slide? Or did you stick to 2.5? Likewise, was needle clip position as per 350b?

I’m not sure where I got the starting point to use a #135 main, it may possibly be from another 250/350 conversion thread that was using pods or something like.
The one size increase on the pilot jet was to compensate for the pre mix but I’m 1 3/4 - 2 turns out on the air screw so could possibly have used a standard #25.

Any info you can remember would be greatly appreciated.

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Hot Topics / Re: buying from Yahoo Japan auction/Buyee (8th & 9th parcels)
« Last post by Foy(notFox) on October 01, 2022, 09:42:36 PM »
So I bought more bits from Japan but this time used the From Japan site. All the listings are the same as Buyee as they both link to Yahoo Auction Japan (which is very like Ebay) but someone said they were less fussy about prohibited items.

As it turns out the pieces I bought were pretty safe this is a moot point.

The interesting aspects this time I guess is that I used surface mail to save money and also they bundled certain items together for shipping but not in any logical date-purchased or size system

Also when you pick the cheaper surface mail it warns the packages are not tracked so you are taking a bit of a chance on it even arriving.

So I bought 5 listings which were all pretty small apart from a swing-arm. I paid for the items on 11th, 14th, 29th of June and they bundled the items from the 11th and 29th together in a smaller box with shipping of £35.33

I paid the shipping on that on 14th July and it arrived this week which is like 10 weeks. We are back to the immaculate packaging again so am not sure what happened with #7 with the XJR barrels flung in a box  :-\

Each listing as 1280 Yen purchase-price which works out to almost exactly £8 depending on exchange-rate on the day.

So for my total outlay of £59.31 I got the parts below.

from From Japan Limited

car exhaust pipes clearing Customs ok

precision packing

no idea what this says

sticker on box seems to share....

....certain data with stickers on packed items

little hand-made tags on the parts

£7.99 for exhaust-pipe/header

£7.99 for pair of exhaust pipe nuts

£8 for LH handle switch

The 2nd (bigger) parcel which I paid shipping on a couple of weeks later (29th July) hasn't arrived yet but a tracking ref does show for it on the site. Perhaps over a certain cost you get a tracking ref. It certainly doesn't give daily updates when clicked but it's better than nothing I guess.

So I don't know if I'm saving that much using surface mail as the prices seem similar to before but I'm thinking the prices overall have jumped and if I choose airmail again it will be a shock.

The seller I got all the cheap CS2E bits from appears to be breaking a whole bike but has not yet listed big pieces. I'm hoping the silencers get listed as these are rather scarce. I've just bought the exhaust/header pipe so technically the bigger bit should be shippable as it would have the same carbon in it but I'm not sure they'll see it that way  ::)
Aircooled RD Tech Help 200cc and Below / Re: RD200 DX replacement pistons
« Last post by Phil Featherstone on October 01, 2022, 08:27:25 PM »
Hi the 1E8 piston runs rectangular type rings and the 397 runs a dykes top ring. you can run the 397 pistons with the dykes(L) ring but they are actually for the earlier 397 model.
One place said that the labyrinth center seal normally does not need replacement. Definition: The meaning of LABYRINTH is a place constructed of or full of intricate passageways and blind alleys.
After receiving the first contact, I sent off my crank because my motor failed the leak down test and the seal spins freely on the shaft. I cannot visualize a seal that is full of passageways. One person said that the suction from the opposite crankcase sucks the seal closed. My leak down test did not include a suction on the opposite side. (I later found that my head bolts were not very tight.)
Crank Works will disassemble my crank and inspect it for a modest fee. He might tell me that the seal is O K.
Aircooled RD Tech Help 200cc and Below / RD200 DX replacement pistons
« Last post by DeepThought on October 01, 2022, 08:08:06 PM »
Hi all,
I’m in the process of restoring my late father’s old RD200 DX that was stored in a shed for the best part of 40 years after an accident. I’ve stripped down the engine and am now considering changing the pistons since I’ve had an issue trying to remove the old set of rings which are stuck solid, and the carbon build up is proving stubborn to remove.

The bike itself was registered in 1977 with the chassis/engine serial number starting with 1E8. According to my parts list, I need pistons (I’ve measure the across the bore and it still looks within spec, so I think another set of standards will be fine) with a part no 1E8-11631-00-97 which I haven’t yet found. However, I’ve come across a pair of NOS RD200 pistons, including rings on the net, but these have the part no 397-11631-00-96.

Can anyone advise if the latter is compatible with my bike model? They look identical to what I have…

If not, I’ve seen a RD200 1977 STD piston on Yambits which I’ll keep as plan B. Was hoping to use original Yamaha parts if poss…

Any advice would be much appreciated,
I sent it to Crank Works. Thanks.
His labor is $375, not counting parts or shipping. 
Aircooled RD Tech Help 250cc and Above / Re: problems with rd400g wont rev in lower rpms
« Last post by 5port on October 01, 2022, 07:37:48 PM »

I guess you are in North America somewhere?

The airbox is the same, apart from 2 items,  7 and 2. I thought you might mention number 7 (interconnect joint) is shown upside down, unless you fitted it that way?  It must go pointing down into the lower chamber, not up! BTW, the 250 part 7 is different, like a rubber 3-tube bent pipe! 
Now, part 2 is the air filter. The one shown is a 400C/D/E  USA one with square metal tubes in the middle. You must not use the one with the metal tubes! You need the open one for the 250/400E.  This is not the normal air filter element for a USA 400C/D/E.

CDI bike has no electrical connection of CDI to the rest of the bike electrics. CDI works with no battery.

Many RD owners think they have cleared all their carb circuits. Please say how you know the angled Pilot orifices are clear? How do you test this?

Ed Erlenbach is correct.  But I haven't read him say to space the YZ85 reeds back to fit. You need to have the inlet opened up to allow the YZ85 reeds to fit fully in. This is best done by a tuner who is used to opening-up ports properly. The reed inlet space is not a very thick casting and it is easy to break through. Also, you need the sides by the reeds to be properly clear of the petals for their full deflection, plus a bit, or the petals can jam at the sides and hang open.
I think you have work to do here before you go further. Get the reeds fitted properly. This will cure the issues with the boots and the carb positions. Also 9mm spacers make about 10mm with the extra gaskets. That is a hell of a large increase in inlet volume and it is also primary compression volume so it reduces primary compression. Also, you are making extra places for air leaks with spacers.
OTOH, if you want to follow your tuners advice, why come on here with your problem?



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