rbbeng60 Posted November 30, 2011 Report Share Posted November 30, 2011 Hello to all I've just purchased a bultaco 159 project, which needs a hole lot of work. It's stripped now and I'm working out what I need. I think it's a 350 can anyone tell me the piston diameter so I can work it out for sure. Thanks Ben Quote Link to comment Share on other sites More sharing options...
smelling123 Posted November 30, 2011 Report Share Posted November 30, 2011 Hi Ben, 159 is a 350 (or actually 325ccs). Not sure of piston diameter but the 250cc version is 70-72mm so if yours is in the 80's it'll defo be a 350. cheers Stu Quote Link to comment Share on other sites More sharing options...
Johnny Posted November 30, 2011 Report Share Posted November 30, 2011 Good luck with the rebuild. I'm rebuilding an M80 and I've had a lot of excellent advice from the guys that know a lot more about Bultos than I do. Best advice I can give is don't be afraid to ask. Quote Link to comment Share on other sites More sharing options...
woody Posted November 30, 2011 Report Share Posted November 30, 2011 The bore of the 325cc engine is 83mm, stroke is the same as the 250cc which is 60mm. Check the engine number stamped on the right side crankcase, the first 3 numbers tell you which type it is, if it is the correct type it will start 159, same as the frame, the remaining numbers may match the frame but not necessarily as they sometimes differed when new. Quote Link to comment Share on other sites More sharing options...
pedronicman Posted December 1, 2011 Report Share Posted December 1, 2011 (edited) The original standard bore of a 325cc sherpa is 83.20mm BUT your engine could or could not have re-bored to a bigger size over the years and necessarily be still on the std bore. So you will need to measure the bore to see what piston size you need. ta Edited December 1, 2011 by pedronicman Quote Link to comment Share on other sites More sharing options...
rbbeng60 Posted December 1, 2011 Author Report Share Posted December 1, 2011 Thanks for the help everyone. I will get the micrometer on the piston in work today. I got the case split last night in work and it doesn't look to bad. The engine number is a 159, matching numbers. It needs new rod bearings so I'm going to make a jig for splitting the crank and re pressing back together. I will get some pictures up on hear soon. Unsure what to do with the frame yet. I was thinking of ripping off a puma style bike but I'm not sure yet? Any idears would be a great help Thanks again Ben Quote Link to comment Share on other sites More sharing options...
rbbeng60 Posted December 1, 2011 Author Report Share Posted December 1, 2011 Just had a look at the barrel and piston 84mm That's had a bit take out of it. I take it you can get rings for 84mm ?? Quote Link to comment Share on other sites More sharing options...
pedronicman Posted December 5, 2011 Report Share Posted December 5, 2011 Just had a look at the barrel and piston 84mm That's had a bit take out of it. I take it you can get rings for 84mm ?? yes Quote Link to comment Share on other sites More sharing options...
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