Rev Limiter on 426?

I think I have decided to keep my WR. One question still has me searching for an answer. My bike runs fine know that I have rejetted it and cut the throttle stop. I was wondering if I cut the throttle stop too far because now when I open up the throttle full, it seems to hit a rev limiter. Do these bikes have limiters? Or is would my main be causing it to stutter at WOT. My jetting is basically stock with a OBELN #3, Baja Designs insert and snorkle removed from air box. No other engine mods. Would it be worth trying my 160 main jet in place of my 165 or will that be too lean. I ride in Michigan 600-1200 ft. Fuel screw is at 1.5 turns out.


They do have rev limiters. I beleive it is 11,500. Or at least thats pretty close.


Drop the main to a 160 or 158 and the studders will go away. The misses are a rich condition. Also check the jetting in my signature. I am running your bike, mods, and baffle. Just finished a 3 week process of probably 50 jetting combinations. Don't think I can get it better than it is. Single tracking today and its wonderful. Good luck.

Rev limiter is set at 10500 RPM for the WR426 and 11500 RPM for the YZ426.

Maybe you need a bigger MFJ with your stock #200MAJ now that you can achieve WOT....

OK, not sure which advise to follow. One says drop the main, the other says to put in a bigger main. :) tctrailrider,

If I put in the 160 is it necessary to change the MAJ and Pilot circuit? Your jetting is much different than stock all over the place. I have a 160 main and a 38 pilot in my garage, but that is it for extra jets/needles, (except for a 170 MJ with won't get any use here in MI). My MAJ is stock (#200) and my PAJ is also stock (#?). What relationship will the Main and Pilot Air Jets have if I change the MJ and PJ and leave the Air Jets stock? Would it be a waste of time to try or would you recommend that I just bite the bullet and buy the two air jets?



To change from D to E taper you need to go approx. 5 smaller on the MJ. Missing is normally a rich condition and I think this is the problem. As far as the air jets you will get the best performance with the correct match. To drop the main to 160 should help and dropping MAJ to 160 will make it even better. Changing the MJ is quick and easy so little time is invested in a try. For about $30.00 you can get the adjustable PAS, 160 MAJ and EMP, you really should give this a try, its wonderful.

What is the Pilot air screw? I looked at the schematics of the carb and am confused with two of the jets. If you look at the exploded view on Yamaha's parts catologe, ref 22 shows a standard of jet #65. I thought this was the PAJ, but then ref 23 shows a standard jet #75? The Jet #65 is at the bottom and the #75 jet is in the back of the carb. What is the stock PAJ? 65 or 75? Where is the best place to buy what you suggested?


The Main Air and Polot Air jets are next to each other on the back of the carb. Take off the black plastic attachment that the air boot clamps to. The one on the right is MAJ and should say 200. On the left is PAJ and I think 75 is stock and this works well with a 42 PJ. The PAS is an adjustable PAJ. Makes it easy to change as you try different PJ. You can get the PAS from as well as other jets. If you go with this setup the PAS should be out just less than 1/2 turn with the 38PJ. My EMP 3 1/2 is clip 3 with a small washer under the clip. An ELP3 or ENP4 would be the same as mine without messing with the washer. Hope this helps.

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