Thanks to Woody's suggestion i contacted John Collins about 2nd hand barrel and head for my 191,he's pretty sure he can sort one out for me.Can someone tell me what the Standard bore is and what the oversizes are please.

According to the Hayes manual the bore is 83`2 stroke 60mm for the 325 (326cc) Sherpa this could vary on later models I had an early 325 and the piston went up in .25mm up to 1mm

Yes, 325cc engine all have the same bore which didn't change until the 6 speed 340cc engine

Thanks for that,now i can see if i can get a barrel with as many oversizes as possible left in it.

Hello all. If you have to I would say someone would still have liners for this model. so if you can only get a barrel that is on it`s last legs that is not hopeless. Just stick a new liner in it. Bully Lover.

Cheers, on a related issue John also said there were pattern pistons that went beyond the genuine ones max oversize.Anyone had any experience of these? As i haven't got a barrel to look at i'm not sure how much meat they have on them beyond the +1mm.

There is enough to take them out to the 340 piston and oversizes

If you are finding it hard getting a barrel

http://www.ebay.com.au:80/itm/ws/eBayISAPI.dll?ViewItem&item=140728110681&ssPageName=ADME:B:SS:AU:1123

Maybe someone can tell me is the later 199 barrel the same as the 159-191,as in do they still have 159 stamped in the the top and if they are different what is the difference

Just spoke to peter at Bultaco UK today about pistons for my 191 and as i'm in the process of sourcing a second hand barrel for it i asked which ones were compatible.The barrels on 159, 183 and 191 models are the same but the timing is different on the '78 on 199,199A.

So is a 159 Piston different to a 199 piston then?

I don't think the pistons are different because i was told that the 325cc barrels could be bored out to take the 340cc pistons and their oversizes.The porting must be different if the timing is so i suppose the position of the inlet and exhaust could differ as well.