Popping on aceleration

[dickerson]

I have been working on my sons 2007 RMZ250. It pops on acceleration, idles fine. I have checked all the jets, air filter, fuel screen in tank. Checked valve clearance and could not get my smallest feeler gauge between. I only have a couple of feeler gauges from MSR that I used on my YZ426F, now ride YZ250. Is this a sympton of tight valves? Any ideas would be appreciated!

 

[Matt90GT]

Acceleration or Deceleration??

Popping on decel is more common, cause by either an exhaust leak or lean pilot or plugged up pilot or hotstart being stuck open.

You have to get the right tools to work on the bike. Get a feeler gauge set that covers the minimum and maximum specs for the bike. If you have a set for a 426, they should be fine on most other modern 4stroke MX bikes. You will have to get the valves in spec first.