yz450f maintaince

[STEAMER450]

I have a 04 yz450f with two seasons on it I have clearanced the vlaves twice and want another season out of it it has started to backfire more and more often what would be a budget preventative maintaince ?

[CaptainKnobby]

just go ahead and rebuild the the top end or get someone elese to that knows how so they can check the condition of the valves because if u blow that sucker up it will probally cost u $2000.00.

[new2blu]

I have a 04 yz450f with two seasons on it I have clearanced the vlaves twice and want another season out of it it has started to backfire more and more often what would be a budget preventative maintaince ?

Have you jetted correctly? This is the most common cause of backfiring on de-accell. I have a 03 WR450 that will be able to get many more seasons out of with no need for a new top end.

[642MX]

So have you adjusted the valves twice, or have you checked them twice?