My 77 KZ650C engine....

Ok the guy i bought it off had the bike in a dry shed, the headers were off and he didnt have anything covering the exhaust ports. the engine is not seized, he pushed with his hands on the kick start to show me it kicked over, the shed was super dry but the bike was pretty dusty. I was thinking of giving it new oil,oil filter, spark plugs, cleaning the carbs, air filter, whatever else to the engine and trying to start it(of course with the headers/exhaust) Some people are telling me i should tear it down make sure its not rusted. Im thinking if i would have to tear it down and rebuild then maybe i should try seeing if it would start first with some TLC.

Should i just tear it down or at least see if it starts before checking the pistons

I personally wouldn't tear it down before at least trying to start it up because you may find it runs fine. I would spritz some oil into the cylinders and use the kicker with the spark plugs removed to gently cycle the engine several times to distribute some oil on the cylinder wall before starting; you may want to remove the cylinder cover and get some oil on the cam lobes and bearings and top end too before starting. My rationale is if things are really dry damage could occur before the oil circulates to the dry parts. I wouldn't start it without an exhaust system attached or you may burn some valves. Be sure to check the fuel tank for goo and rust; put in new fuel, replace fuel line, and add an inline filter or you may foul the carbs you just cleaned with gunk from the tank or petcock. If you do get it started, I would run it till warmed up good and change the oil again. Ed

alright that seems to make better sense. i will try this once i get me the header/exhaust. thank you for replying