i just got it bored out. every thing is good there but the spark plug is the same old one that the piston burned up on the first time. i got a block off kit and im mixing the gas. that's also ok. but it run for 15 mins, i rode it around the house, it then reved (sorry...bad speller) high, almost died, went back up and back down and died. it was really hot and a little bit of smoke. i let it cool for ten mins and started it agian. it ran good for 5 mins and did the same thing. so do i need a different needle and seat(still stock, every thing is except for the block off kit, boreing, piston, piston bearring) or is it some thing else?