My 94 xr600 was smoking bad on start up. I replaced the valve seals, started it up and let it idle for 5 minutes then rode a little and all seemed well. Anyways, I go to trade it in today and the dealer starts it cold and revs it up repeatedly and it was smoking. I let it warm up easy so I didn't know it would do this. I don't want to tear into this pig again if I don't have a good idea of a fix. I am thinking it needs rings. I want to sell it so I don't want to do any extra work. I didn't do the ring when I was in there because I have the service records from the previous owner. It had a bore and new piston late in 02. I looked at the records closer tonight and saw that 3 months later the cam chain was replaced beacuse of "overheating". If the bike got hot could that have toasted the rings?