i got about 300 miles out of my stock crank after i put 70ccs on it. it died peacefully. it actually stopped when i was stopped at a stop light. tried to crank it over and it wouldn't move. i didn't force it at all. got it home, big end bushing melted itself. some people say it's cause i run non synthetic oil. i just think 9000-ish rpms need a bearing w/ a 200+ pound dude sitting on it.
now i got a rito.
i had an old brass bushing crank.