Need Major help wr450

I have a problem that I cant seem to get a hold on my 05 wr450 flutters on wide open throttle... I know what it feels like to "float" the valves but this is not the case from just at idle it runs great mid runs great but when you open it up it stumbles? I have done the jd kit and even cleaned the carb still has problem...Upluged tps still same thing....put new plug in it still same thing...The only mods I have done to it was cutting the grey wire and uncorked the exuhaust (gytr) Can anyone help?

WOT is main jet either too rich or too lean.

I followed the jd kit to the tee how could it be the jets? it started running crappy about 10 miles after I cut the gray wire could that be it?

Mine was too lean when it did that

Try one up on the main and see, might be a little lean wot.

Changing main jets is easy in the field, with the right tools. You need a 17mm box end wrench to pull the plug at the bottom of the float bowl.... drain the fuel first (petcock in OFF position). Using a small 1/4" ratchet with an 8mm (maybe 6mm) short socket, the main jet is easily removed. You should always start the threads by hand when re-inserting the MJ, so as not to muck up the threads. One thing to note: The Needle Jet may come out with MJ. Have someone hold the throttle wide open when putting the needle jet back in.... make sure the throttle turns smoothly/ needle is not hanging up.

Really, once you do this one time, you'll see how easy it is.

Get your bike fully warmed up, and test by going one up and one down on the Main Jet size. See which direction is better, and fine tune from there.

There are some great FAQ's and threads on this site about jetting and trouble shooting.


Open and print the jetting database by Indy at the top of this page. It is a bullet proof jetting guide for the WR. The only way to accurately fine tune the jetting on your scoot is with an exhaust gas analyzer. All of the modern dynos come with them. There is a finite range of exhaust emissions that works for all internal combustion engines. The dyno doesn't lie.

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