GT80GUY Posted March 7, 2015 Share Posted March 7, 2015 picked up a 1978 yz80e the other day and the top end was siezed. split the cases and everything to do with the crank is rusted and pitted to sh#%. but I do have an old gt80 (close in year) and I was wondering if I could use that. it all seems very close, similar connecting rod (if not the exact same) and same crank shaft. but the weights on the yz80 are a bit thicker, anybody know if I can use it? a used crank is like 200$ online Link to comment Share on other sites More sharing options...
slice Posted March 7, 2015 Share Posted March 7, 2015 Yeah just bung stuff in and see if it works shall we, no honestly you need to measure everything and if anything is different then forget it as you will end up breaking something. If the crank weights are different then it's a sure bet that other stuff is different to. Similar is not the same as the same. I do wish you luck with it tho. How's the GT80 engine? would that fit complete? Link to comment Share on other sites More sharing options...
GT80GUY Posted March 7, 2015 Author Share Posted March 7, 2015 Yeah just bung stuff in and see if it works shall we, no honestly you need to measure everything and if anything is different then forget it as you will end up breaking something. If the crank weights are different then it's a sure bet that other stuff is different to. Similar is not the same as the same. I do wish you luck with it tho. How's the GT80 engine? would that fit complete? so if the weights are 2 mm slimmer it'll break something? the gt80 engine is missing quite a few pieces, I measured the connecting rod and it's the exact same length as the yz80. the yz has a 2mm difference in piston. and the shaft is the same as well. Link to comment Share on other sites More sharing options...
GT80GUY Posted March 7, 2015 Author Share Posted March 7, 2015 Yeah just bung stuff in and see if it works shall we, no honestly you need to measure everything and if anything is different then forget it as you will end up breaking something. If the crank weights are different then it's a sure bet that other stuff is different to. Similar is not the same as the same. I do wish you luck with it tho. How's the GT80 engine? would that fit complete? oh and another question, the weights were pretty rusty so I cleaned them up with a wire wheel (yz weights) but there is some pitting. will that throw the weights off balance and cause a problem? Link to comment Share on other sites More sharing options...
slice Posted March 8, 2015 Share Posted March 8, 2015 I hate to say this, no really I do, but there comes a time when it's just not worth the bother. If as you say the thing is in a right state then ask yourself what is it actually worth? then look around a see if you can get a better one and use the one you have for spares. I hate breaking bike for parts but sometimes you have to really look at the thing and say "it's not worth the trouble or expense" if everything is rusted and pitted then find another one that isn't. Link to comment Share on other sites More sharing options...
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