i know this is an old thread.... but i have a 2002 raptor 660, stock motor, and it even says on the airbox lid that i should run a minimum RON of 91? i tried running regular unleaded and she was backfiring and bogging a little. switched to 89 octane (plus) and it ran a little better. so i tried switching to 92 and it ran great! with the stock motor would it be bad to go any higher?