98 zr 500 carb cleaned carbs checked everything over went for a mile ride on way home to pull plugs to check had a melt down on exhaust side of piston clutch side where do i start looking for the cause before putting in new piston. thanks
Burning up on the exhaust side is usually a sign of a lean condition. If you are going to do the top end it would probably be a good idea to pull the engine and do the crank seals. Intake flanges (boots) should also be renewed. A sled this age is probably sucking extra air from one of the above causing lean burn down. Check out the skirts and look for scuffing, this may be a sign that it is lacking lubrication. Make sure your oil system is is good working order. While apart, check out the exhaust and make sure there are no holes in the pipe and that all joints are sealed. When carburetors are cleaned make sure they are CLEAN. When completed, mix the fuel 50:1 in the tank and jet rich for the first 100 miles. This helps reduce friction during break-in. May foul a plug but you are insuring a long life on a new engine. During dyno sessions I've seen as rich as 10:1 fuel air ratio to help keep things cool during the beating the dyno gives them. Hope this helps, nothing worse than burning a brand new set of pistons.