Too Rich, Too Lean

1 reply to this topic
  • Powerband

Posted May 02, 2000 - 08:31 AM


I have a 00WR400F and need to make some adjustments. My bike sputters on the top side of almost every gear and occasionally pops/backfires when I am backing off the throttle. Please correct me if I am wrong, but I think the stock PJ=42 and the stock MJ=168 on a 00WR400F. My question is:

If my bike is sputtering on the top side of almost every gear, does that mean I need to go richer on the MJ or Leaner?

If my bike pops/backfires when I am backing off the throttle ocasionally, does that mean I need to go richer or leaner on the PJ?

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  • Bill

Posted May 02, 2000 - 12:09 PM


Just like I did when I got my jetting straight. You may be hitting the rev.limiter. The bike revs so freely and is making power all the way, you may not realize your hitting the rev limiter. Take the bike out to an open area and get it in fourth or fifth and see if the bike has the same results. If your coming off a 2-smoke, you may be over-revving.

Some popping on decelleration is OK. But it should not sound like popcorn popping.

Let us know.....


86TT225, 98CR80, 99WR, WR timing, throttle stop trimmed, air box lid removed, White Bros head pipe, silencer and air filter. Odometer and headlight removed. Moose hand and mud guards.


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