YZF 450 popping on decel

3 replies to this topic
  • asg5265

Posted May 18, 2011 - 05:23 PM


Here we have an issue that so far has us perplexed. The bike pops on decel, yet starts just fine, which indicates the starting circuit is working fine. We are concerned that one or more of the valves MAY have an issue as shortly after acquiring the bike we checked and adjusted all 5 valves and one was more than a little bit out of spec. It was loose to roughly .035", and the remainder were within spec! Bizarre!! We ran the bike after and it would still run "hot" as it had previously with plenty of heat coming off the motor. I do have previous experence with 250 4-stroke motors and suspected a clogged pilot jet. Yes, we did have the carb apart and cleaned it, although some question exists as to wether or not it was a thorough cleaning job. It seems to perform well enough, although I've yet to own a new 450, so I can't say definitively. With that being said, it bears to reiterate how well this bike starts, but the "decel pop" plagues our sanity (sic!) and feeds our fears of intake or exhaust valve troubles of which ALL four stroke owners dread. If anyone would care to make a suggestion or two, we'd take that into consideration. Thanks!

  • georgedoggy

Posted May 18, 2011 - 05:32 PM


in my opinion, you need to go bigger on the pilot jet. that would be the first thing id do.
if it pops on decel its definately the pilot !

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  • grayracer513

Posted May 18, 2011 - 05:53 PM



  • mazak500

Posted May 18, 2011 - 08:59 PM


mine was popping on decel and it was because my exhaust got loose. 08 yz450f

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