ok. short story is with my 2010 yz450f the first summer i had it, middle of a race the oil drain bolt worked itself loose. few laps later i pulled in, noticed it, replaced it, topped off oil, no issues. few months later a bog started, completely random, but cause some very sketchy situations for me. i have done everything i can think of, bike related. ( kill switch, fuel pump oring, head gasket, etc). the random bog still happened when the motor heated up. i took it to the shop in town and they told me the piston needs to b replaced. so i did with a piston with a cp 13.5 compression piston. i was running vp's u 4.4 fuel. cp says fuel needs to be at least 100 octane nd the u4.4 is only 96 or 98. could that cause the bog yet? cause started using vp's c12 fuel, and havent noticed it at all. but i dont ride for very long as im afraid of the bog. anyone here have any thoughts? i posted in the yz450f forum but no one had ideas. could it b the fuel i was using just wasnt enough? or could i have warped my rings again?