myson Posted January 24, 2010 Report Share Posted January 24, 2010 (edited) Hi,How much did the sherpa engine change between 1971 M-80 and later models 72 on? In particular internals ie clutch gearbox etc? Cheers Edited January 24, 2010 by myson Quote Link to comment Share on other sites More sharing options...
wayne_weedon Posted January 24, 2010 Report Share Posted January 24, 2010 Not an awful lot. Clutch centre rotor changed design. Not sure about any ratio changes. The gearboxes are quite bullet proof. Do you have a specific problem? Wayne.... Quote Link to comment Share on other sites More sharing options...
woody Posted January 24, 2010 Report Share Posted January 24, 2010 Selector forks thickness were changed, mainshaft size changed, so did the mainshaft bearing clutch side, clutch hubs changed a couple of times, clutch spring tensioning went from nuts to pins back to nuts, cranks changed, crank seal carriers changed, shape of the clutch side crank weight changed to match the casing shape. Maybe more. On the 325, the cylinder design was changed and from 159 I think, the liner was thicker so these can be bored right out to 340, early 325 can't as liner too thin. Most of the gearbox/clutch changes above were around 1973, other changes came later. Becuase of the changes it sn't possible to interchange all parts from model to model. They may look the same at a glance but they aren't, not everything will swap/fit. Quote Link to comment Share on other sites More sharing options...
myson Posted January 25, 2010 Author Report Share Posted January 25, 2010 (edited) Thanks guys, No specific problem but have chance of a haynes manual 1972 onwards and I was wondering how relevant info would be for my M-80 engine etc. also had offer of some engine spares so now I know what to watch out for cheers Edited January 25, 2010 by myson Quote Link to comment Share on other sites More sharing options...
wayne_weedon Posted January 25, 2010 Report Share Posted January 25, 2010 Haynes manual is Just OK! Most Bultaco people will have one, but the 5 speed engines are so basic it's rarely needed. Wayne.... Quote Link to comment Share on other sites More sharing options...
myson Posted January 25, 2010 Author Report Share Posted January 25, 2010 Cheers Wayne, its just for reference because it may be in bits for a while! Myson Quote Link to comment Share on other sites More sharing options...
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