I'm guessing I'm WAY rich on mixture?? (JD kit)

Took my bike up today for the first trip since installing the JD kit. I think I'm way too rich. I set it up for the 3,000-6,000' but it would barely run. I could screw the zip-ty fuel screw in all the way and it would not even affect the idle. It was spitting and sputtering like crazy. I guess I will go to like the 1st or 2nd groove on the blue needle & see if I get close. Oh yeah...I read that one guy had alot of trouble from 1/8-1/4 throttle, with no load until he cut the gray wire. Could that be the case? I do have the dreaded stumble and the gray wire mod is the only free mod I haven't performed. Is the red needle richer or leaner than the blue? What is it normally used for? Chuck

The Red marked needle is leaner and would be your next choice. It falls between the Blue marked needle and stock. The Red needle is for higher altitude and warmer temperature. Try it in the middle clip position to get the idle mixture leaner and balance the jetting between low end and mid-range. (Is this a WR450?)

Keep the main jet at a 168 for a WR426(per instruction sheet) or a step leaner 165 for the WR450.



Like JD says Red #3 or #4 with a 160 main should get you close. What bike do you have and is it corked or uncorked?

'03 WR450,all the free mods except grey wire and GYT-R insert


Check over your installation and try using the red needle in the middle clip position with a smaller main jet, preferably 165 from my experience with the '03. The combination of model, setup, and conditions looks like the setting could be a step leaner.

The 450 has a slightly different carb model than the 400/426 and the red needle will evenly lean the lower throttle range.



rekless- I think you should disconnect that grey wire before you spend more time adjusting your jetting. With the grey wire connected, ignition mapping is changed so that the bike will run better with the stock jetting, exhaust and airbox plugs in place. Disconnecting it will disable this map. It is an easy mod, and easily reversable. Remove your fuel tank, and pull the large white plug appart. It's about 6 inches from the ECM(the square plastic box on the right side of the frame between the triple clamps). Use a small screw driver to depress the little tab inside the plug that hangs from the ECM, and pull the grey wire out. The wire can then be plugged back in, should you ever want to. :)

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