81 kz550 ltd engine ?s

i just bought a 81 kz550 ltd for $100 its rough but is what i was wanting anyways the motor sounds like it has a knock at idle the more rpms you give it the more th knock goes away any ideas on what to check? Also if needed where could a rebuild kit be purchased?

Kz, knocks are not good.start with the basics. all 4 pipes get hot. compression is roughly equal, valve clearances ok. carb sync close. oil pressure. in spec. 4's running on all 4 are seldom knockers. change oil and look for copper in oil/filter. a 100$ bike generally is just that, do what you can before tear down.luck g

could be just because the carb's are out of sync or it could be your clutch basket or or or or or!!!!

by the way the kz550 ltd is one of the best wheelie machines ever so if it isn't to bad make it work you'll have fun on the little bugger.