'06 WR450F Idle Speed Problem

[phattaxman]

I have a problem with my 2006 WR450F. The idle speed varies quite a bit. Even when the bike is resting on the kick stand with no one around, the engine will speed up and slow down on its own. While riding, if you close the throttle you don't know whether you're going to slow down or if the high idle speed is going to keep pushing you. Yesterday, I went over a little jump and the engine stalled in mid-air. That was fun.

The bike is completely stock -- no mods whatsoever. Any suggestions?

[Solo]

Why is it when you have a problem like this you find the site that is sure to have the answer at midnight on a Friday?? Welcome to the site!! I don't have your answer but I'm sure someone will chime in as soon as they sober up some.

[odonnks]

That'll be a combination of the AIS kit and jetting. Mine did the same till I removed the AIS. (Air injection system) a polution control device.

This site's store has about the best removal kit available.

You'll want to do some of those mod eventually. Here is a site that covers them pretty well. Its for the WR250 but the WR450 is identical.

http://www.thumperfaq.com/free_mods.htm#YZ

[OneToGo]

Follow the above link by Odo..good advice.

You will want/need to mod your bike - at least the freebies before it runs like a propper thumper.

Yep, the idle problem is a combination of jetting/AIS and ACV that in ways will become apparent to as you educate yourself through this site.

I also recommend some jetting basics - its best to understand the cause and effect - go to the Jetting forum and read up on the stickies.

When you have the mods done then this is a great site to fine tune out any little niggles. ENJOY

[Matty05]

Definately will be lean jetting. You need to replace the 45 pilot jet with at least (and most likely) a 48 pilot jet.

Have a look in the jetting sticky at the top of the post list for Indy's chart. Great stuff!

[phattaxman]

Thanks for the advice. I'll work on the jetting and order the AIS removal kit.