XR650R Sound Check (CA)

Has anybody been checked lately in CA? If so, what was the result (with which pipe)? I have the HRC tip, so I'm wondering if it will pass.



From what I've read, some folks with the HRC tip have passed and other haven't. My HRC tipped bikes were never tested even though I rode by rangers numerous times in the last two years. I also made turn downs for my HRC tips and that may have reduced the perceived sound, thus making my bike a less obvious target to rangers.

I would be absolutely amazed if the HRC tip was 96db or under using standard Ca. testing procedure. I've seen test results that put it at 98-102 db depending on who is doing the testing.

Get a Baja Designs baffle for it or make your own turn down.

I agree with you Mokuleia in that I too would be amazed if the HRC tip truly passed if tested correctly. While I've read where some guys have passed with the HRC tip, there may be other factors at play (improper testing procedures, environment, equipment calibration, training, etc). I've also read where someone was tested twice in the same day by different rangers at the same park with results that differed by > 3db :)


At the VCMC charity ride last year, there was a mandatory sound check by the USFS. I have the HRC tip on my 650R and it passed no problem. In fact the guy jokingly asked, "Is it running?" The test is done at an idle, not when you are hammering down the road.

Do you think a HRC tip is enough to open up the exhaust? If so how much are they. I have been considering buying a slip on for my XR650R, I currently have a tip on it and a baja designs screen on the air box cover. The air box screen really opens up the air flow, I am rejetting for it, but it is pretty nice.

It seems to depend on where in the rpm range you want the power. Its generally accepted that you will at least not notice any increase in low end torque with the HRC tip vs the stock tip. All the gains are in the mid to high rpm range. If you want to keep your low end, its almost opened too much.

As far as noise, its what I would call very loud. Standard testing procedure in Ca. is done at half the bikes max rpm, not idle. I remember seeing a list of tested bikes on some USFS website, and the 650r was tested at 3250 rpm. If I find the link again I'll post back. It is pretty mellow at idle though. Eric has some info on the Pig pen FAQ page indicating 3500 rpm was 102 db with the drilled stock tip, 8 feet behind, and 8 feet to the side (the HRC is louder still). I believe the standard testing distance is much closer.

Get a Baja Design baffle for the HRC insert (supposed to meet 94db) or make your own turndown from plumbing p-trap or actual exhaust tubing.


try this link


Here is one page I found that at least describes the testing procedure. 20" from the tailpipe at a 45 degree angle (its the same for atv's). The rpm during the test is determined by a formula described in the article.

That is the bible JWS, thanks :)


At the VCMC charity ride last year, there was a mandatory sound check by the USFS. I have the HRC tip on my 650R and it passed no problem. In fact the guy jokingly asked, "Is it running?" The test is done at an idle, not when you are hammering down the road.

Here's yet another example of a XR650R passing, but person doing the USFS test positively did NOT do the sound check correctly. The engine RPM for the XR650R 'must' be at 3,250 RPM in addition to many other clearly documented requirements and there is a 1.5 dba margin of error. Here's the official link of where the engine RPM is specified for for variious motorcycles and ATV's.


Here's just some of the details that I copied down a ways back from the official test specifications & requirements of how testing is 'supposed' to be done, but make note that official testing by a ranger that's enforcable 'must' be done with a 'type 1' sound meter (that's calibrated), otherwise the testing is void from enforcement. I've personally never been tested, but I've seen the tests being done and talked with various rangers and other represenatives involved with this testing and I can tell you there's definitely a margin for error here because not everyone I spoke with was completely familiar with the test equipment or all the environmental issues, etc.

*** Location Of The Microphone Of The Sound Level Meter. (7-1-94) ***

a. The microphone of the sound level meter shall be located twenty (20) inches - one-half (1/2) inch behind the exhaust. If there is more than one (1) exhaust outlet per side, the microphone of the sound level meter shall be located with reference to the rear most outlet. (7-1-94)

b. The microphone of the sound level meter shall be within one-half (1/2) inch of the height of the exhaust outlet. (7-1-94)

c. The microphone of the sound level meter shall be at a forty-five (45) degree - ten (10) degree angle to the normal line of travel of the OHV. (7-1-94)

d. The longitudinal axis of the microphone of the sound level meter shall be in a plane parallel to the ground plane. (7-1-94)

e. The axis of the microphone of the sound level meter shall be oriented as specified for field response by the manufacturer. (7-1-94)

04. Attachments Prohibited. No wire or other rigid means of distance measurement shall be attached to the sound level meter measuring system.


01. Test Site. The test site must be a flat, open surface free of large reflecting surfaces, other than the ground, such as parked vehicles, signboards, or hillsides located within sixteen (16) feet of the (OHV) being tested and the location of the microphone of the sound level meter. (7-1-94)

a. Ambient sound level. The ambient sound level, including wind effects, at the test site due to sources other than the OHV being measured shall be at least ten (10) dB lower than the sound produced by the OHV under test. (7-1-94)

b. Wind speed. Wind speed at the test site shall be less than twenty (20) miles per hour. (7-1-94)

c. Persons in test area. While making sound level measurements, not more than one (1) person other than the operator, the measurer, and the assistant, if necessary, shall be within ten (10) feet of the OHV under test or the microphone of the sound level meter, and that person shall be directly behind the measurer on a line through the microphone of the sound level meter and the measurer. (7-1-94)

02. Test Surface. The surface of the ground within the test area shall be paving or hard packed earth, level within an average slope of five (5) inches per foot and shall be free of loose or powdered snow, plowed soil, grass of a height greater than six (6) inches, trees, or other extraneous materials. (7-1-94)

03. Position Of OHV. (7-1-94)

a. For two (2) wheeled OHVs, the operator may sit astride of the OHV, in normal riding position with both feet on the ground. If this is not possible because of the seat height of the OHV, an assistant may hold the OHV by the forks, front wheel, or handlebars so that it is stationary with its longitudinal plane of symmetry vertical. If an assistant is not available to assist in holding the OHV upright, the operator may use a box, rock or other object to rest his feet upon to steady the OHV, so long as the OHV longitudinal plane of symmetry is vertical and stationary.(7-1-94)

b. For three (3) wheeled and four (4) wheeled ATVs, the operator may sit in the normal riding position with one (1) or both feet on the footrests. (7-1-94)

04. Operation Of OHV. (7-1-94)

a. If the OHV has a neutral gear, the operator shall run the engine with the gear box in neutral at a speed equal to one-half (1/2) of the rated engine speed or one-half (1/2) of the red line speed specified by the manufacturer as compiled in the Off Highway Motorcycle and ATV Stationary Sound Test Manual. (7-1-94)

b. If the OHV has no neutral gear, it shall be operated either with the rear wheel(s) at least two (2) inches clear of the ground or with the drive chain or belt removed, or the clutch, if the OHV is so equipped, disengaged. (7-1-94)

05. Engine Temperature. The engine of the OHV being tested shall be at a normal operating temperature.

Here's the contact info I had from a few years back on where I obtained my copy of the Stationary Sound Test Manual for Off-Highway Motorcycles and All-Terrain Vehicles (includes Test RPM data back to 1985).




2 Jenner Street, Stuite 150

Irvine, CA. 92618-3806

(949) 727-4211 (voice)

(949) 727-3313 (fax)


1235 Jefferson Davis Highway, Suite 600

Arlington, VA. 22202-3261

(703) 416-0444 (voice)

(703) 416-2269 (fax)


You are correct. It was obvious to me that something wasn't right with the testing. I mean really, most if not all bikes would probably pass at an idle. I think the testing that day was done just to show that it could be done should the USFS want to enforce it.

I'm glad they're doing the testing and I think they're probably out to ge the people at the extremes as opposed to someone on a 650r with an hrc tip that's probably somewhat close to passing since there's a 1.5 dba margin for error. Earlier this year, I rode up to a ranger who was checking on what looked like an abonded vehicle and he never once made any comments about my bike being too loud and that was with the Moriwaki exhaust installed. There were probably ~15 bikes in our group who momentarily stopped by his vehicle and mine was not the loudest, but it was far from being as quiet as my yougest sons XR200.

From looking at all the data from the State of CA, it looks like a crap shoot to me. I'm entering a Hare Scramble next week at Carnegie, so I think I'll take my chances with the HRC tip. I will bring the opened up stocker just in case though.

Thanks for the input,


I am so glad that I do not have the issues that you Cali riders have. The only person that has ever bitched about my uncorked 650R is a Soccer Mom that was trying to yak on her Cellular. But she was a hottie and I laid some rap on her and she left smilin.

Are they really that anal on the Left coast that they will send you home if you are 1db over the limit? Hell in the VA mountains noone can here you srceam!!

Well I did the race yesterday, and all I can say about the sound check was, if they checked all the bikes, they would still be there today!

Not in Ca but I was checked with a big gun and the quiet baffle inserted. It was at 96-98.

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