James Dean or whoever else.

My 02 WR426 has sat for about a month without being used. Now it won’t start, not even a pop. Took the plug out and was bone dry. Checked the spark and was good. Took the carb off and noted that the accelerator pump no longer works, obviously the problem.

Is there anything else on the carb I should check? And what’s the deal with the ac pump?


pull your float bowl. Turn on your fuel >> is there flow?

When is the last time you did a THOROUGH carb cleaning?

The loss of your AP WILL NOT stop your bike from starting. One TT completely disconnected his AP. [The 98,99's are notorious for seizing the AP due to corrosion >> crappy design!]


You’re right, the float needs to be checked. It has been quite a while since the carb has been cleaned. I did the tip test (gas flowed out), choked it, twisted the throttle 15 or 20 times wide open, and hot start button, but nothing worked.

It really threw me off because I just completed the coil on top of spark plug mod and so naturally when it didn’t start I was thinking it was due to lack of spark. After verifying it did have good spark, just for the heck of it, I replaced the plug with a new CR8E. The result was the same, not a single pop and a dry plug.

Today, I got as far as getting the carb off and noticed the lack of ap. The carb was full of gas. I took the ac pump apart and looked clean. Tomorrow I’ll check the float operation and clean the carburetor.

Thanks again.

Disassembled the carb today, looked clean. Had the float bowl on the bench to try and figure out what’s up with the accelerator pump. The check valve on the bowl for the ac pump was working (cleaned and checked it with a vacuum tester), and the 2 o-rings looked brand new.

With the float bowl filled with clean solvent and the ap installed I simulated the ap with a small allen wrench. Nothing happened until I covered the port on top of the carburetor bowl. The when I pushed down the diaphragm that part of the ap circuit worked: the check valve compressed, solvent was drawn into the pump and then forced out the port on top of the bowl.

I don’t get it.

So is there another check valve in the accelerator pump circuit?

Problem solved! After the carburetor was completely disassembled and every hole blasted with carb cleaner and compressed air that corrected the problem. The AC pump is working again, and the bike started today on the first kick. The only new part I had to buy was a new pilot screw since I lost the o ring and washer from the old one, doh! Thanks Kevin for carb cleaning the tip! Just send me a bill, LOL!

Temps are now in the 50’s and humidity is around 59 percent. I upped the MJ to a 160 and raised the needle from 3 to 4, PS is out 2 turns.

I’ve got Mike Deans coil on plug mod in place and it looks GREAT! Can’t wait to test!!!

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