WR400 Exhaust Systems

I am looking to replace the exhaust on my 98 WR400 and was wondering what everyone else is running - I don't want it to be too loud and the replacement is more cosmetic than power enhancing. I have been looking at the Pro Circuit T4, as it is cheap (369), but if anyone has advice for or against and if you know where the best deal is, that would be great.


I thought the PC was loud...???

It sounds as if FMF's new QUIET silencer is reasonably quiet. That and maybe a Power Bomb header?

I have the PB w/ a Stroker SX-1 silencer/SA. It is better power than stock w/ baffle in.


'99 WZ/YR (you choose!) with ALL YZ mods, de-octopused, DSP Doug Henry airbox w/ velocity stack, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, OEM YZ tank, IMS YZ seat.

[This message has been edited by NH Kevin (edited 08-10-2001).]

I just got my exhaust system in today! White bros E series Pro Meg Shorty. It is a thing of beauty! I can't wait to put it on tonight! I won't be able to ride it until tomorrow though. I paid 240 for it and the adapter kit for the WR, which is just some additional mounting hardware. From dyno tests this is supposed to be the best pipe for power, but it is loud from what I hear. I will let you know how I like it and how it sounds.

NH Kevin - how's the Stroker SX-1 sound, I understand that is the way to go in combo with a Power Bomb Header, is it way louder than stock?


The SX-1 takes the bark out of it, but it is louder than plugged/stock.

It is more quiet than unplugged stock.

I would really like to see the dyno results on FMF's new Quiet silencer...

I know Dirt Rider mag, which really pushes stealth, rated it very high, with an "improvement" in power.


'99 WZ/YR (you choose!) with ALL YZ mods, de-octopused, DSP Doug Henry airbox w/ velocity stack, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, OEM YZ tank, IMS YZ seat.

[This message has been edited by NH Kevin (edited 08-10-2001).]

I would consider finding a used YZ system and using it. You can probably pick one up for $100 (maybe less if someone wants to trade for yoour WR pipe) and for the cost and performance difference between a YZ system and an aftermarket system. You might be money ahead.

I have a White Bros and will be mounting a YZ system soon and comparing. Stay tuned for the results.



99 WR400f, YZ timed, MX-Tech suspension, Scotts steering damper, White Bros E-Series (12 discs), tapered header and a/f. Kouba T-handle for the fuel screw. Works Connection billet throttle tube and frame guards. Cycra Pro-Bend, triple clamp mount handguards. Thumper Racing rad guards, Renthal Jimmy Button highs, YZ Tank and IMS seat, YZ number plate, odo removed, EKP #4, 50PJ, 175MJ at 500-1000' Thanks James Dean!

I just made my first test ride on mine with the White bros pro meg shorty. Huge diffrence! I love it. Money well spent, and I am still forest legal!

I agree with bill. The stock YZ, especially the 01, is the way to go. All the reports have said its just about the best and you can find them supper cheap.

If your really resourceful you can add a spark arrrestor. I drilled out the rivets and inserted a screen, I can tell you it does take some muscle. Works great!!!

Mr T

Mr Toyz, sounds like a cool modification to put a screen in that pipe, but Im almost positive that wont count as a spark arrestor in the eyes of the law. Im fairly sure that to be a leagal spark arrestor, it has to have the US Forest Service stamp on the pipe/spark arrestor itself? Now if you just bought a set of metal stamps and a hammer.......


1995 EXC 400

AMA Dist 37

02 520 EXC (soon)

I am very happy with my new Power Core Q pipe w/ power bomb header. It added some needed power in the low end on my 99 YZ timed WR400. Sound levels are low but the power that the stock pipe restricted has been unleashed! Hipersports packaged the whole deal for $450.00.

You are correct you do need the Forestry stamp. But....It's worked so far, been inspected three times, no problems. Kept my mouth shut and let them look.

My silencer doesn't say "closed course only" any more... :)

Mr T

I just took a dremel cut off wheel and cut the weld off the stock YZ plate. Probably should be inventive with some SA material when I repack the silencer.

Hello there,

I just put on the T-4 Pro Circuit not too long ago. I was going for the Yoshimura, but they were back ordered. I'm so glad I went for the T-4. It is a complete system as you know. Talk about power! I rejetted to a 175 main and a 45 pilot. The bike is basically stock otherwise with the exception of the stop cut down. This bike, a 2000 WR 400, just flat out RIPPS!!!

Have fun and good luck.


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