what my friend has is one 99ZR600efi that had 1500 trouble free miles. On goes the D+D pipe and chip. 15 miles later the piston sqweeked and tightend up in thhe cylinder mag side. On tear down the piston was fine on top and exhaust side was not melted just tight. Called D+D they told my friend that the chip would either work or not it would not cause this type of burn down. they suggested that the oil pump starved that cylinder. So we got a replated cylinder new piston and sent them out to swain tech for plating. we changed the oil pump aand check valves and reassembled the top end. Broke the motor in a field ran it about 16 miles ran fine plugs looked brown the oil pump was using alot of oil (turned it way up). we went to munising for the first ride we pulled the ethatnal plug to add a little extra fuel. 14 miles later the piston tightened up and we towed it home. we pulled the plugs and they look good but you could feel the engine was tight and scraping. we were not running hard if anyone has been in munising lately you will know its tough to run fast mougles gallor. so i'm sure we will need new pistons maybe a jug and i'm sure D+D will say something is wrong with the motor. its almost like a 660 drag chip is in it ran like a bandit for short pulls, but burns down when holding steady speeds.