Jetting tricks for a 02 wr426??

I've seen a lot of talk about jetting with the carb still on the bike. I installed a zip-ty mix screw and it hits the chain tensioner when i try to spin the carb. Also I have to remove the coil to get it to spin far enough. Any tricks? :)

The main and pilot can be done with out moving the carb at all. The pilot is a little trick, but a short screw driver and a mirror helps.

As far as the needle adjustment I have'nt got the touch to remove it without taking the carb atleast partially out.

I just got my jetting pretty close (02 wr 426 ) 168, 45 pilot, stock needle with clip at 3, and 1 1/2 turns out. Then I put the jd kit in and it launches much harder now!

good luck!!!



I haven't tried yet but it looks like a task just getting the bowl off to get to the jets without moving the carb. :D I just picked up the bike a couple weeks ago so I need to take a look and see what it's jetted at but it seems to run pretty good as is.....problem the guy installed a WB e-series but it had no plates or end cap just wide open. Ordered the plates etc but they backordered :) and can't give it a good ride until I get it USFS approved. He may have jetted for wide open so we'll see how it runs restricted some.....from what I've read the system works better with some restriction. What pipe/muffler are you running?

If you take the bottom nut off 17mm you can access the main and the pilot jet. The main jet is a 6mm and the pilot jet is right in front of it - use a small short screw driver. Steal this wifes little vanity mirror to get a better view.

Try the jettings I have above if you are under 2000'. If you bought the jd kit- 170 main, 43 pilot (stock), blue needle at 4th clip, 1 1/4 out on air screw. The top end is about the same as before, but the bottom and mid range is the closest to my cr500 I have ridden.

Unless you need to get to the pilot air jet or main air jet, you just have to take that nut off.

I am running the stock pipe with the gytr insert that is cut off. My buddy had a e series pipe and it was really loud. It had a little more grunt, but very loud for the mountains. Jetting( with the discs in) was about the same as with the bigger insert.

Thanks again for the info. I'll check it out and see what jets I have. I decided to install a 03 YZ450 ex cam to pick up the auto decompress so will wait until I get that installed to rejet if needed. :)

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