Does anyone know what the db level is with a stock set up with the baffle removed?
If the bike will not pass the dB test with the baffle out, should I bother with the airbox mod, using the stock exhaust.
Welcome to the board Pooley!
I have been checking in with this board for a while now and finally registered so I could ask some questions.
I am eagerly awaiting my upcoming purchase of a WR426 and wanted to ask some questions of the Michigan members.
I will be joining the CCC in Michigan and would like to know whether or not the 426 will pass the 94 dB sound test with the "free" performance mods - baffle, airbox, stop and grey wire. I want to have the best performance I can but want to comply with regulations.
It won't pass with the baffle out.
Pooley, Congratulations on the new bike. You will love it. I am not positive but I think that the stock pipe with the Vortip insert will come in below 94DB and have more power. You mite also look into the FMF Q series I think it claims to be around 94DB. Try not to stay up nights thinking about your new bike.
Originally posted by Greg C: Try not to stay up nights thinking about your new bike.
Try not to stay up nights thinking about your new bike.
Too late...I've been having trouble falling asleep ever since I decided to sell my street bike and get a trail bike. By the way, anyone looking for a 94 Honda Magna, 750cc V-4, with tons of goodies? I'm in Michigan.
By the way, I ran a sound check on my bike this weekend ('01 WR w/all "free" mods, including removing the baffle from the stock exhaust set up) and it ran at an average of 106db. With the baffle in it ran at an average of 94db.
Just an FYI for you noise level checkers, but in order to compare apples to apples, make sure you are measuring your exhaust noise level consistently. Set your sound level meters (SLM) to slow response, "A" weighting. Fast response and/or "C" weighting will result in hugely different numbers. ("A" weighting on the SLM electronically mimics the way the human ear perceives sounds of different frequencies.) I was part of the tech inspection crew for a dual-sport ride a few weeks ago and was really surprised how quiet the stock exhaust was from a fellow WR rider's bike. 82 dBA at idle 20" from the tailpipe tip.
the ccc is pretty picky about db. readings,
at the rites of spring ride my buddy made
some different exhaust tips for his wr400,
one blew 96db. another one with a turned
down tip was 94 db. the limit is 94.
be sure to go to the rites of spring ride
next year, good people, good fun.
The only other tips I can think of is to hold the SLM away from your body when performing the test. Your body can reflect the noise and skew the readings. Again this is for consistency in your measurements. A wind screen on the microphone will reduce or eliminate wind noise, which could give false high readings. Also, if you have a way to calibrate the meter, that would be a good thing. That way your measurement should compare with any law enforcement officer's SLM. If you do ever get cited for being too loud, I would demand to see calibration records for the SLM they are using. An SLM should be within 0.1 dB of the calibrator's standard to be considered accurate. (My previous job was as an Industrial Hygiene technician where I performed OSHA-required sound level surveys for job-related noise exposure.)
Our particular dual sport club measures the sound at idle 20" away from the tailpipe at a 90° angle. The sound level is considerably lower there than at 45°. It all depends on the criteria established by the sanctioning body or by the riding area's/State's requirements. It's my understanding that the local requirements in my area are to be less than 94 dBA at 35 mph, 50 feet away. Since that would be a difficult measurement to make, we substitute the idle measurement 20" from the pipe. This seems to satisfy everyone.
My 99 WR400 was the loudest of the entire group of over 100 different bikes (various makes and models) at idle with a measurement of 87 dBA. I have an FMF Megamax II muffler with a quiet core insert and 12 disks.
Rich, thanks for the measurement technique information. I had the weighting set to C. I will retest using A. Also, I had the meter at a 45 deg. angle, 20" away from the exhaust outlet with the tip of the sound meter aligned with the end of the exhaust outlet. Any other tips?
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