My 2000 mxz 600 has blown up. I rebuilt the engine with factory pistons and had bored it out 10 thous. I checked and cleaned the carbs and emptied the old fuel. The sled started up with a few pulls and was allowed to run for a while. Coolant was flowing properly and everything seemed to be running alright!!!!!?? My problem is that when the sled reaches 100km it wants or does cease up. I can start it up immediately and go again with the same problem occurring. The exhaust pipe canister becomes cherry red. What problems can I have?(timing? computer?) plugs are good. There are no restrictions in the pipe.