Help

My bike runs good and crisp, right until you get to the upper RPMS. Then it sounds like it is bogging and sputters. Plug looks perfect. It does not have a power valve. Of corse,,it just started doing this after I put a FMF pipe on it. I put the needle where FMF suggested and it was worse. I moved it back,,,still same problem. If the plug looked bad, I could understand, but it looks perfect..nice and chocolate brown. Any suggestions??

Oh no. A YZ490, summon the jetting gods and sacrifice a toad....... (j/k)

Bill, did the FMF instructions say to go richer?

You said high RPM but not where the throttle is..

Is this part throttle high RPM or WOT?

Most likely you'll go one leaner clip and one leaner main

because sputters with brown equal rich.

If it were lean it would bog completely without sputtering (usually)

Edited by carver

Gonna give it a shot! thanks,,,What pisses me off is I had it perfect!! Starts first kick, every time!! If it does not pan out, I will be selling a FMF pipe and go back to the DG,,no problems with it. Thanks again!

Oh no. A YZ490, summon the jetting gods and sacrifice a toad....... (j/k)

Bill, did the FMF instructions say to go richer?

You said high RPM but not where the throttle is..

Is this part throttle high RPM or WOT?

Most likely you'll go one leaner clip and one leaner main

because sputters with brown equal rich.

If it were lean it would bog completely without sputtering (usually)

Ended up being electrical. I put a coil from a PW80 on her and she rips !! I have to learn how to ride her again!

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