2000 YZ426 Jetting Help

Can anyone give me some suggestions on jetting my Keihin FCR MX39 carb? I'm a Michigan Rider and don't have any problems with the way I have it jetted now, but I feel it could get better. I'm running with a 160 Main, a 42 Pilot, and 3rd clip from the top on the Needle. Also, I'm using the standard Exhaust(silencer) with a White Bros. High Boy Header. I installed a R&D P-38 Accelerator Pump and that helped, but I still think MAYBE I could get the bottom end acceleration a little quicker. Please share some thoughts here. ANY suggestion will be greatly appreciated!

I dont know what a P38 accelerator pump is but, im betting it has a limited shot. You need to get us some specs, like elevation. Explain what the P38 is supposed to do, and Im sure we will be able to get you some decent info.

The needle they delivered in the '00 is way too lean just off the pilot. They corrected this for the '01. The best twelve bucks you can spend on a '00 YZF is the stock/standard needle out of the '01.

So IMO before you do anything else you need to try the '01 needle.

Hope this helps.


Can ya post the numbers, I thnk it would not matter if its an 01 or an 02 but the needle number is the item we need



The P38 is a replacemnt accel pump supposed to allow for a cleaner dilivery off bottom....

Thast all I know

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