1972 Yamaha AS3 restoration (exhaust & another harness)

[Motty]

Hi Graham, welcome back
I'm sure I am not the only one who would welcome you to post more than your current once a year.
If it is only cables you are waiting for, can't you get some made up, or would that spoil all the fun?

Sent from my Moto E (4) Plus using Tapatalk

[Foy(notFox)]

Hi Graham, welcome back
I'm sure I am not the only one who would welcome you to post more than your current once a year.
If it is only cables you are waiting for, can't you get some made up, or would that spoil all the fun?

Sent from my Moto E (4) Plus using Tapatalk

Thanks Motty. Out of the 9 possible cables I am only missing 1 so it's not that which is stopping me finishing the project. I guess the most tangible issue is that the engine is on +.50 pistons/bores and I'm assuming it'll need a +.75 or +1.00 re-bore and you never see AS3 pistons/rings in those sizes. Also I don't trust anyone to de the re-bore. I guess I should really get my measuring tools out instead or fearing the worst.

I'll also be updating my other threads. SS50 one next. What spurred me on today was that I got a new camera and could therefore get good pics of the more recent purchases.

That and the fact I wimped out of a roofing/gutter job today due to the miserable weather   

[Gr8uncleal]

Enjoying the read Graham.

I've just picked up a near complete RD125B and also an AS3 in boxes to add to my collection.

I'll check later anyway, but I'll be lazy and just ask you to confirm that your AS3 came with Mikuni carbs and not the Teikei (TK) that were fitted to the RDs? In the boxes were a pair of Mikunis with the original grey cables still attached, but also a pair of TKs.

Now to a far more important question! Back in the day (1980s?), were a band called "The Chaps" from your neck of the woods? I ask because they did a version of the song "Rawhide" and in it was a line that went something like ".........dreaming of pints of heavy in East Kilbride"! I have the single in my collection somewhere!

All the best.

Alan

[tony2stroke]

https://www.ebay.co.uk/itm/Yamaha-AS1-AS2-AS3-O-s-Pistons-And-Rings/293490807500?hash=item44556a52cc:g:jcQAAOSwv3teVABp

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[Gr8uncleal]

https://www.ebay.co.uk/itm/Yamaha-AS1-AS2-AS3-O-s-Pistons-And-Rings/293490807500?hash=item44556a52cc:g:jcQAAOSwv3teVABp

you can use RD125 rings for your pistons, they are the same.

https://www.ebay.co.uk/itm/Yamaha-RD-RD125-NOS-2-Sets-Genuine-Piston-Rings-396-11610-20-0-50-size/264645261057?hash=item3d9e163701:g:RsQAAOSwU0VeMEf1

Thanks Tony!

That's useful for me, as I got AS3 first oversize and RD125 standard in my box of bits.

Alan

[rodders]

Just a note of caution here guys. The 396 RD125 rings on ebay linked by Tony are mine and are dykes type, AS3 as far as I am aware are 307 and keystone type. There may be some cross over as on the YR5 where pistons and rings are available in both types, but I would suggest this is confirmed before purchase. I dont have any 307 rings. If you want any of the parts I have listed on ebay 'Rodders44', PM me through here.

[tony2stroke]

Just a note of caution here guys. The 396 RD125 rings on ebay linked by Tony are mine and are dykes type, AS3 as far as I am aware are 307 and keystone type. There may be some cross over as on the YR5 where pistons and rings are available in both types, but I would suggest this is confirmed before purchase. I dont have any 307 rings. If you want any of the parts I have listed on ebay 'Rodders44', PM me through here.

YES AS SAID CAUTION ADVISED, there are some AS3 with RD parts on a crossover, 183 is prefix on the pistons, rings 2nd oversize 183-11610-20 and keystone type, sorry got confused, 307 is correct prefix for AS3 but AS1 or AS2 pistons being piston port, same porting,  same stroke and same bore size should work, but some AS3 do have RD heads & barrels with reed valves instead of piston port as we have all found out.



Thank you for pointing that out Rodders, don't want to confuse the issue.


SORRY I get lost in all the part numbers sometimes, I have removed the link to avoid confusion.

[Tailchaser]

Alan,

This little ditty:

https://www.youtube.com/watch?v=IWMDuRZBnnw

cheers,

Jeff

[Gr8uncleal]

That'll be the one!

[Foy(notFox)]

Enjoying the read Graham.

I've just picked up a near complete RD125B and also an AS3 in boxes to add to my collection.

I'll check later anyway, but I'll be lazy and just ask you to confirm that your AS3 came with Mikuni carbs and not the Teikei (TK) that were fitted to the RDs? In the boxes were a pair of Mikunis with the original grey cables still attached, but also a pair of TKs.

Now to a far more important question! Back in the day (1980s?), were a band called "The Chaps" from your neck of the woods? I ask because they did a version of the song "Rawhide" and in it was a line that went something like ".........dreaming of pints of heavy in East Kilbride"! I have the single in my collection somewhere!

All the best.

Alan

Hi Gr8uncleal. When you say an RD125B and an AS3 that could mean a few things lol. Apart from one library pic I've never seen a genuine UK RD125B. There are loads of the USA, ones which have many differences, and they seem quite common in France so it would be interesting to know what you actually have.

To me AS3 means an actual (non-RD) AS3 but in France they seem to call the early RD125 models AS3s which is understandable as the engine/frame numbers started AS3-2*****.

About the carbs. Like you I don't have my machines close to hand but I'm 99% sure the AS3 (proper) had (un-painted) Mikuni carbs whilst the early RD125 had a TK carbs which were painted black. Main difference was the RD125 ones bolted to the barrels whilst the AS3 ones fitted onto a spigot.

Re 'The Chaps' and the song referencing East Kilbride: I've never heard of this which is strange as I'm quite knowledgeable about music but more so as the very same day you asked this a friend asked me about another EK band. She was asking if it was true that Roddy Frame from Aztec Camera wrote a song about a pub in East Kilbride.  I spent some time Googling the Roddy frame thing and it was inconclusive but I'm sure there was never a pun in EK called The Diplomat, which is what his song 'Down The Dip' is supposed to be about   

[Foy(notFox)]

Thanks for the update Foy!  Worth getting the AS3 sorted.  You can get the cylinders/pistons checked out.  You seem to prefer working with things that are right and that is good.  You might well find that they are good used +0.5 !     Even slightly tired could be good enough with new rings for a rider!     Even a bit more worn might be usable for a while.  You know how it is, if you put it together, you will find better parts!       If the bores are really past it and you cant get pistons etc, you could have them relined back to standard!
So, check those bores etc and get it running.  Cheers

5port

Yes. There's no real reason it should need another re-bore but I'm just preparing myself for every eventuality. Actually I think back in the 70s/80s if anyone had problems with these bikes they were probably re-bored locally with non-OEM +.50 parts. My AS3 and RD125 both have this 'feature', plus the ubiquitous chapped and mangled wiring near the battery, and weren't high-mileage bikes. I'm pretty sure no one in UK back then was doing leakdown tests etc and I remember ads in MCN for cheap re-bores so if a fault arose the answer was re-bore. But why not +.25 and why cheaper pistons used? When I got the remains of my bikes they were only about 14 years old and no-one had parts for them or had even heard of the AS3, including dealers so I have my doubts that they were serviced properly even when newish.

Re-lining is something I'm interested in as it means redundant stocks of STD pistons and rings can be used but it doesn't get mentioned much. Is is a lot more expensive? Can anyone actually do it correctly? (cutting ports in the sleeve for example)

[Foy(notFox)]

https://www.ebay.co.uk/itm/Yamaha-AS1-AS2-AS3-O-s-Pistons-And-Rings/293490807500?hash=item44556a52cc:g:jcQAAOSwv3teVABp

Interesting listing tony2stroke but, being a pessimist/cynic alarm bells ring for me when I see listings where parts apparently fit lots of machines and the seller doesn't flesh-out the description for someone new to the hobby. Someone with more knowledge of these bikes may know about adaptability within similar models but I just stick to the parts lists.   

Off the top of my head the only 183 piston part the AS3 used was the gudgeon-pin and these parts seem to all be 183 (YAS1)   

[Foy(notFox)]

https://www.ebay.co.uk/itm/Yamaha-AS1-AS2-AS3-O-s-Pistons-And-Rings/293490807500?hash=item44556a52cc:g:jcQAAOSwv3teVABp

you can use RD125 rings for your pistons, they are the same.

https://www.ebay.co.uk/itm/Yamaha-RD-RD125-NOS-2-Sets-Genuine-Piston-Rings-396-11610-20-0-50-size/264645261057?hash=item3d9e163701:g:RsQAAOSwU0VeMEf1

Thanks Tony!

That's useful for me, as I got AS3 first oversize and RD125 standard in my box of bits.

Alan

Sorry if I'm saying stuff that's already been said lol but am just going thru all the responses in the order they were made (cheers guys) and yes the 307/AS3 pistons had 307 rings which were then replaced by 396 pistons and rings on the 1st RD125 models but then the USA models used 466 pistons and reverted back to 307 rings which seems to have applied in UK Europe also by time of RD125B ('75) so in summary...

you can use RD125 rings on AS3 pistons as long as they aren't proper (396) RD125 rings 

or put another way...

you can use 307 rings on 307 pistons and 466 pistons. you can only use 396 rings on 396 pistons

[Foy(notFox)]

Just a note of caution here guys. The 396 RD125 rings on ebay linked by Tony are mine and are dykes type, AS3 as far as I am aware are 307 and keystone type. There may be some cross over as on the YR5 where pistons and rings are available in both types, but I would suggest this is confirmed before purchase. I dont have any 307 rings. If you want any of the parts I have listed on ebay 'Rodders44', PM me through here.

Very helpful rodders. Yes afaik 396 rings can only be used on 396 pistons which are very hard to find unlike the 466 pistons used on USA RD125B (which use the 307 rings).

You learn something new every day however as I've always thought there must be a catch using 466 pistons in place of the 396 ones but looked today at '75 RD125 parts list and the 466 pistons show in that.

I don't think there were any (significant) changes to the barrels when these piston/rings variations were taking place so it must be ok to interchange them.

The Dykes rings must've been an experiment. What we really need is (non-USA) Yamaha Parts News from the era. That would have a wealth of information for all models 

 

[Foy(notFox)]

Just a note of caution here guys. The 396 RD125 rings on ebay linked by Tony are mine and are dykes type, AS3 as far as I am aware are 307 and keystone type. There may be some cross over as on the YR5 where pistons and rings are available in both types, but I would suggest this is confirmed before purchase. I dont have any 307 rings. If you want any of the parts I have listed on ebay 'Rodders44', PM me through here.

YES AS SAID CAUTION ADVISED, there are some AS3 with RD parts on a crossover, 183 is prefix on the pistons, rings 2nd oversize 183-11610-20 and keystone type, sorry got confused, 307 is correct prefix for AS3 but AS1 or AS2 pistons being piston port, same porting,  same stroke and same bore size should work, but some AS3 do have RD heads & barrels with reed valves instead of piston port as we have all found out.



Thank you for pointing that out Rodders, don't want to confuse the issue.


SORRY I get lost in all the part numbers sometimes, I have removed the link to avoid confusion.

Thanks tony2stroke. I have no knowledge of the AS1/AS2 but if port/stroke/bore are same as AS3 there's no reason they wouldn't work.