Best Silencer for 2001 426

Seems like everyone keeps asking the same questions about silencers but right now I've got three to pick from and don't know which one will get me the type of power I want. I'm looking at the White Bros. E-Series pro-meg, Pro Circuit T-4, or the FMF Power Core IV (or whatever it is). I want a lot of low end and midrange grunt. I want it to growl (grrrr baby, very grrrrrr), and if anyone could steer me in the right direction it would be very much appreciated.

Well I have not tried any of the pipes. But I will offer this. I just got my 426 yesterday. So, I am till learning everything. Since this is a 4 stroke I will make the assumtion that some auto technolgy applies. That said, if you want more torque down low you need to provide more back pressure in the exhaust. Of course this will hurt the top end.

Good Luck



01 YZ426F #85 Vet C

I am by no means an expert, but I purchased the e series. I have spent the last two days playing with the jetting and the number of plates. I mostly ride motocross. What I found worked best(I was timing starts and then a would clock 50yds just below the limiter) was uncorked stock needle, pilot, but bumped to a 168. The biggest affect was the pilot screw, it ended up 2 1/4 out. I was surprised at the difference the pilot screw made. Much more significant than a 2 stroke. I ride in so cal. Testing at 1000 ft, extemely humid(raining some of the time)

i just got the t-4 and it is GRRRRRRR! VERY, VERY, GRRRRRRRRRRRRRRRR! loud is an understatement! when it idles it will shake my garage door, the wind from the exhaust can be felt about 15 feet away, and when it is wide open it is a mini top fuel on steroids. the white bros. makes better low end power but the t-4 is all mid and up top. this is on a 2000 wr400 so results may vary.


Be careful on the grrrrrrrr. I'm not trying to preach but everytime we piss someone off with noise we make another enemy, that will try to help close down tracks and riding areas because we disturb the peace.


I agree on the noise. I run the stock muffler (?) on my '01 426 and, frankly, the noise gets old after a while. I know it's possible to design quieter systems that still flow well (albeit a bit larger) and it's about time the manufacturers went that route. I've heard KTMs are significantly quieter and look at their weight.

I can't argue one iota about noise. However, Bonez was right on the money about the White Brothers silencer. I'm using the carbon fiber(no discs) that doesn't seem to be any louder than stock, other than a deeper bass tone. It's used in conjunction with the White Bros titanium hi-boy head pipe. This combination really wakes up the bottom end right off idle with very little sacrfice on top. Since the strength of a 4-stroke is hook-up, this combination is a match made in least for me. If either one of these pieces gets damaged, I'll replace it with the same thing. I like it that much!

The problem is....what works for me, may be a disappointment to another rider.

Thanks for helping me out guys. I just read the White Bros. E-series owners manual and they said that you shouldn't run it sans discs, a little confusing since a lot of people say they run it wide open. Also does anyone know where I can find the lowest price on the WB pipe??

The E-series. I have the E-series and am really happy with it. You can adjust the powerband somewhat by adding/removing the discs. The E-series is also a USFD spproved spark arrestor, so there's another plus if you want to trail ride sometime.

In the Dirt Rider shootout(for 2000 YZ426) I believe that the E-series was chosen as the most favorite for on the track. Its also great on the trail.

Go with the E-series. Mine was $250 from Magic racing in Pontiac, MI.

Thats my 2cents.


YZ 426's suck!(all the air they can get)

THROTTLE JOCKEY......because all golf courses should be motocross tracks!

NO!!!!!!!!!! my friend with a 2001 426 JUST got the new white bros r-series muffler, it produces ALOT better power than the e-series.its made of T-6 alluminum, weighs a claimed 3.4 lbs, and sounds smooooooth. UGH! its nice guys, its oval. very nice, its a little shorter than the e-series i think. tucks in good, look at it, its NICE! aight im out.


I also have a WB E-series pipe on a new 2001 YZ426. I love it! I am currently running 10 discs and the spark arrestor cap with no jetting changes at this time. Bike runs good with a cocoa brown plug, but my next move is to tinker with carb settings for fine tuning.

I recently purchased a White Bros. R4 pipe! I really didnt want the R4, and originally wanted the E series but after talking to a nationally renowned suspension and motor tuner (J&M Suspension and Motorwork) he dynoed the 01' 426 with both pipes! The e series had the jump off the bottom with about .3 HP ahead for 700rpm (2500 to 3200rpm right above idle) and after that the R4 tore the e series up! He dynoed the bike with both end caps removed and also w/spark arrestors installed and the results were suprisingly very similar! On WB website the e series is meant to be a bottom to mid power gain, and the R4 is a mid to top power gain! I actually think the R4 has better bottom that the stocker, because now my bike feels like an automatic...i just pop it into 3rd gear and dont really have to shift (sometimes to 4th on fast straights)! I will now bog around berms and instantly rip out of them with ease!

The R4 actually sounds different that the E series. My friend has an E series and they sound the same on the track, but when you ride the bike the R4 is for sure a lot more of a deeper tone that the e is! Well sorry to blab on and on, but hey if Doug Dubach likes the R4 more than the E series then I guess I made the right choice!


For any of you guys thinking about buying a aftermarket exhaust go for it! I thought that the pipe wouldnt help because the dyno's looked the same...but this pipe just makes the pipe a heck of a lot easier to ride and thus makes it more fun!


I get my kicks on a 2001' YZ426!

Friendswood, TX

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