i just bought this 2001 zr 440 sno pro. it had 850 miles when i bought it, i took it out and cooked the piston. guys said it was from runnin last years gas in it, so i replaced the two pistons and rebuilt the top end. all new gaskets. the onyl thing was the gasket set was for a 2000 zr 440 but everything lined up fine. i just recently cooked that piston again....and scuffed up my cylinder pretty bad. its been the same side every time too. the clutchside. i know when it was running right it idled at 4000 and took off at 6 which is right for this clutchkit i got for it i guess. but i have 300 mains in it. i was just hoping someone knew something about how to make some sense of this sled and how i can trail ride it without cookin the piston every time thanks.