aircooled4ever Posted December 7, 2015 Report Share Posted December 7, 2015 Morning all, I have a 175 sherpa in the shed (engine number starting 221) that's been there for 5 years that I feel I must do something with. It started off with the usual scenario of buying a bargain that turned out to be a wreck. Bike was stripped by me and it needs all the usual parts ie rod, mains, piston, rebore etc. On reflection I didn't pay a lot for it so it's a case of do it and ride it or chuck it on fleabay as a project barnfind and put it back into something else. I had largely forgotten about it as I have a few bikes, but what changed my interest was that recently I went to a trial and saw a guy on a blue tank 350 bulto doing really well which made me wonder if it's possible to change the top end? I understand that the 175 was a schoolboy derived bike of the time but was it just simply a sleeved down 250? What does everyone think about conversion, is it possible and what the best conversion and which parts are interchangeable? I welcome your thoughts as I'm normally a fantic man and I don't know too much about bultacos, all thoughts welcome please!!! Quote Link to comment Share on other sites More sharing options...
woody Posted December 7, 2015 Report Share Posted December 7, 2015 They are a 250 engine yes, so converting it to a 250 is easy enough. They have a different chassis from the blue 350 model as they use a chassis from the '76 - '78 250 models, these differed by being shorter and with a slightly different headstock design which used shorter forks and a shallower bottom yoke. This chassis is a nimbler chassis than the 350 and the 250 Sherpas are good bikes, usually overlooked by punters in favour of the bigger model. The 250 isn't lacking in power and a much better bet than 175cc. 4 Quote Link to comment Share on other sites More sharing options...
bondy Posted December 7, 2015 Report Share Posted December 7, 2015 Be a nice bike if you made it into a 250 iv'e just rebuilt 2 x 250 engines. Quote Link to comment Share on other sites More sharing options...
pschrauber Posted December 7, 2015 Report Share Posted December 7, 2015 I had a 175 cc too the engine wasn't bad at all surly lacks top end power but was very controllable in low rews and Speed. Personal I would build it up as it was if most parts are still there as there are so little of them left. As a running and proper set up175cc model it's very collectable. The convert to a 250cc model is surly more competitive. It's up to you it's Your bike. 4 Quote Link to comment Share on other sites More sharing options...
scot taco Posted December 8, 2015 Report Share Posted December 8, 2015 Not sure on the later model ones,but on the older 175 Alpinas I believe a 250 top end will bolt straight on.It would cost more,but you could find a 250 cylinder and save the 175.I,m guessing either way you would enjoy riding it. 1 Quote Link to comment Share on other sites More sharing options...
bondy Posted December 8, 2015 Report Share Posted December 8, 2015 I have a spare 198A (250) barrel and head Quote Link to comment Share on other sites More sharing options...
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