I got an E-series WB exhaust... Now what? jetting? WR400

I bought an E-Series White Brothers Exhaust and pipe for my WR400, 2000. Since I didn't get it new, I don't know if it came with instructions or parts to tune the carb. If anyone bought this muffler or entire exhaust kit, please tell me what you bought and what the instructions said to do to the carb if anything.

Thank you!!! :cry:

Anybody know this? Do you need to rejet with the E-series WB exhaust.

I have the manual and it indicates that no rejetting is necesary, but I'd rather hear it from those of you running it.



You'll probably be fine with no modifications to the carb, but I suspect for "optimum" peformance, a slight adjustment may be needed. I installed the FMF Powercore4 on my 450 and just ordered the JD jet kit right from the Thumpertalk shopping area or go to JDjetting.com directly and when you buy, it will re-direct you there. It was easy to install and has all the specs you need to get it right the first time. The only think I dont like about jetting is the trial and error of dialaing it in. I like it when everyone else has done it, then I can come by and steal their specs and do it only once! Oh, get the extenede fuel screw too, just dont seat it down hard or the tip will break off in the carb turning it into scrap along with your aluminum pop cans :cry:

Thanks. I'll check that out. I was also planning on doing the P-38 mod (Accelerator Pump Cover).

I bought an E pipe last fall. No jets came with it but I think there were some suggestions. Jetting changes depend on how many baffle plates you run. Since you bought yours used you may not have gotten the spare plates and shorter screws for running only a few plates.

You can run only a few plates which gives similiar backpressure to stock, so you may not need to rejet, but why buy the pipe if you don't want better flow? Unless you like the sound or you broke the original and this was simply a replacement and not strictly intended for better performance? :cry:

The pipe comes with lots of plates,maybe 12ish, or you can just take the plate out of the end and run it full open. Generally you adjust the number of plates to tune to your bike and rejet to suit. I did rejet mine.

When I first installed it the temp was very cold and I didn't have a big enough main jet so I ran it baffled close to stock. Now I have it jetted and run it with more plates, like this. I just installed a 430 kit and Hotcams on the weekend so everythings going to change again and I should be running the pipe closer to full open. I realize this isn't a lot of help to you regarding specific jetting but you probably will have to play with it a bit.

Just got my E series exhaust yesterday and was wondering if I would get more power running it completely open (no plate) or with all the plates and the plate at the end?? Noise isnt a problem where I ride........

Hey Nackers,

A good friend that I ride with has that exhaust on his wr426. We made him take off that end plate and he said it made so much difference in a good way.

It made it real loud too! How it should be! :applause:

My mate and I ordered a Procircuit Ti GP system each yesterday off ballards!!!!!! I can't wait till it gets here.

Nice!!! I hate to ask how much :applause:

Im wrapped with mine, cant wait to see how she performs and sounds. Might have to play around with it a bit though-in the instructions for the pipe WB say that in some cases running it totally open can actually reduce power, so I thought I would get the good oil from you guys!!! I cant understand how running it fully open could reduce power...but then again Im not an engineer :eek:


Hmmm, I've seen other folks saying to remove that blank plate marked USFS too. The manual claims more power with it installed. I went from an open DSP Ti full system and noticed a drop on power when I switched to the WB E series with 12 discs and the end plate. I do like that the WB is much more quiet than the DSP.

If I ever want to go fast, I'll have to try to remove that USFS plate and make some noise.

You may want to go up one size on the pilot jet...


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