TOPIC:

ok I overheated the bike! yeah out of oil ( unkown leak i park on a black top parking lot at school) Well the bike would run fine at idle but when you rev it up you could hear a knocking! and if you ride it the bike could not get over 25 and no high rpms ( had to finish riding it to work when it blew). So i took the motor apart (from cylinder walls up)......Hoping to find something broken or missing or hole in something a frog or lil asian guys with matches.......NOTHING! I have no idea what broke? PLEASE HELP!!!!

KZ440 83

Not enough info for a diagnoses, but lack of lube and overheat can wipe out the crank, rod and cam bearings, and extremely rapid wear of the cylinder walls and piston causing a lack of compression.

WHat Steell said. Do a compression test (when you get back together). Sorry to say but should have been first thing you did.

ive never worked on one that small but if it has an oilpan id yank that and look at the bottem end before you put it all back together.if it has bolt in rods like a 650 id pull a couple rod caps and check the bearings . anybody got one of those fancy exploded pictures you guys like to post of one of these motors from a manual? ive never been inside a little one,need idea of what we are working on here.