NMA Sound Test

I have an '02 WR 426, mostly stock, just a pipe (Powercore IV). I am interested in going to an NMA event, but am told my bike may not pass the sound check (98db?).

Any insight would be appreciated. :)

I don't know what the sound requirements are for an NMA event but the Powercore IV silencer is loud. I'm pretty sure FMF makes a quiet core for that model but it will only buy you a couple of dBs. The stock muffler with the GYT-R insert WILL test at 96 dBA or less, depending on RPM requirements. Mine tests at about 90 dBA at 3500 rpm.

Thanks, I guess I am going to try to take it to the state patrol inspection station tomorrow, I think they can do a sound check.

Will post results.

Does anyone else have experience getting their 426/450 through a sound check at an organized event? What pipe/silencer combo did you have? Do you remember the numbers it ran? How did you like the pipe/silencer overall?

Thanks in advance for the info.

stock exhaust with the ttr-250 muffler with drilled holes in hte end its very quiet but still keeps the power.. my friend uses an fmf q but im not sure on hte db levels but the white brothers e series with a quiet core might work and also check out a big gun quiet series.. good luck :D :D :):D

The NMA did a sound check on several bikes and pipes. These are thier results...

Here are some results that I just found: I still have a printed copy of that article. MotorSports News, December '02. NMA: Four Stroke Silencer Test

I'll paraphrase thier results...

Honda CRF 450R Stock: 97db

FMF "Q" 97 db :Loss on top, mid and bottom Grade: C

Pro Circuit T-4 95 db :Soft off bottom, revs out good: A-

White Bros. E-Series 97 db :Early increases, signs off early: B-

KTM RFS 520 SX Stock 94 db

FMF "Q" 92 db : Engine revs freer, but less power : B

CRD 92 db: Decrease in power, early sign off: (Not FS "Approved"):C

KTM RFS 400 EXC Stock 89 db

FMF "Q" 92 db : Power increase over entire range: A

CRD 88 db : Noticable decrease of power, early sign off: C

KTM RFS 450 EXC Stock 90 db

FMF "Q" 92 db : Pulls faster, longer and harder than stock: A

CRD 88 db : Noticable decrease of power, early sign off: C

Suzuki DR400Z Stock 91 db

FMF "Q" 94 db : Good response through range: A

CRD 91 db : Substantial gains, good top end pull: A

Yamaha WR250F Stock 88 db (Is the baffle still in?)

FMF "Q" 94 db : Power increases through entire range: A

White Bros. "E" 96 db :Power builds from bottom to top: B-

Yamaha WR400F Stock 99 db

FMF "Q" 97 db : Good thru mid, top like stock: B-

White Bros "E" 98 db :Good power, but sound... : C-

CRD 96 db :Better response, power gains, good top end: A (Chris, I want your pipe!)

No YZ's were tested, and it does not describe the modification state of the bikes tested. Also, the article states that CRD (Ligne Racing) was in the process of becoming Forest Service Approved.

Last time I was sound tested I failed with a Q and PowerBomb

They wanted 96DB or less, I was at 97-98. This was at the Wet Duck poker run at Walker Vally last year. One of their own club members was riding a KTM 520 with a Full Yosh. loud system. I told them to basicly kiss my butt. Double standard or what! They let me ride after that.

I now have the New Q endcap and Im well under 94db.

Later

Eric

According to the MIC standard you were within linit they give an allowance of 1.5 + or - on the DB

if it was 98 yes but 97 shoudl have passed no questions

I posted a link to the MIC Standards Book for sound testing as well

Here Ya Go

Sound Test Standards

I have been tested at several NMA events. My wr450F with all the mods, and stock exhaust with the PMB insert tested at 94db.

So, bottom line. If I haul my old butt out of bed at 4:30 Sunday morning to drive two hours to this poker run in Capitol Forest, WA, and fail by a couple db, will they send me packin? :D Let me ride once and tell me to fix it before next time? I have never met any of these guys (cascade family m/c) nor been to one of their events.

Anyone? :)

In the MIC Standard (Adapted by All States)

It states many provisions for proper testing and conforming. If more people would start taking these bozo's to task on the test methods as provided by the MIC Standard, we would have a better chance at enforcment PROPERLY.

RTFB

Read The Freakin Book

go armed with info if you get tagged check the equipement they use, check for calibration, check for sound test area per the BOOK.

If they want to play the game learn how to play BY THE BOOK

My experience with NMA events is if you are close you should be alright. A guy I was riding with initially tested at 102db and they kept adjusting the measurement angle and rpm's, his score card was marked 98db.

Thanks, I'll let you know how it goes.

:thumbsup:Passed. :)

FMF Powercore IV, tested at 4500 RPM was 96db on my WR426

the guy next to me had a KLX 300 with a White Bro's Eseries running 7 discs and he tested at 95db at 3900 RPM

TTR125 stock was like 87db, don't know what RPM

:thumbsup:Passed. :)

FMF Powercore IV, tested at 4500 RPM was 96db on my WR426

the guy next to me had a KLX 300 with a White Bro's Eseries running 7 discs and he tested at 95db at 3900 RPM

TTR125 stock was like 87db, don't know what RPM

Well, had my WR426F tested last week, its all stock muffler and had the "Vortip" and it measured 90db. With the Vortip out, it was about 95. I know they will be bringing these numbers down each year. So co-riders with KDX 220's rolled through with 84 db's.

I have an '02 WR 426, mostly stock, just a pipe (Powercore IV). I am interested in going to an NMA event, but am told my bike may not pass the sound check (98db?).

Any insight would be appreciated. :D

Well, several years ago, they were at 98 for liquid cooled and 102 for air cooled. The liquid numbers are coming down. Its at 96 DB now. Now I also know if you have a spark arrestor and do fail by a smidge, they will let you go, but tell you to get it handled. Its not like they'll put you on the trailer, well, atleast, it wasnt last time I checked in, but they could be clamping down now :)

Stock pipe with a thumper racing insert. On a 2001 WR426 at 4250 RPM 91 db.

Measured at the VCMC Gorman Enduro Qualifier. The bike runs much better and stronger. Still meets Cal standards. I recommend the stock siliencer with a good insert. It is spark arrested and runs really strong.

On race days just take out the insert. :)

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