I was in M1 Position only and No Load.
I used Idle and all RPM data was me twisting the throttle and looking at the RPM gauge that has a resulution of probably +/-100

I was at about 20" (probably 20-24") and about 45 degrees 40-50.
It was for entertainment use not SAE Certification (of course).

I found more info and a case study
http://ohv.parks.ca.gov/pages/1140/f...2004-31-06.pdf

and a good read here:
http://www.dirtrider.com/features/14...est/index.html

Both of these have many examples.

No Load during my test. And there is a BIG DIFFERENCE

My Elevation is 830 Feet just an added piece of info that may have absolutely no bearing on the situation. But it is data and I'm an engineer.

SlapDrum

 

[QUOTE=SlapDrum;345511]I was in M1 Position only and No Load.

It was for entertainment use not SAE Certification (of course).

Slapdrum,
I agree and the intent is not to say that we should do this particular test, only that if we pick a standard that defines the test conditions and we all do it the same way, then we can keep a list of Pipes, Mods etc., to see how affect the dB and then anyone can look at them and weigh the performance Vs dB levels.
Since this is a stationary test, it will be easier for anyone to do -and even an inexpensive sound level meter from Radio Shack will give a pretty accurate reading.
The meter that I used for my test is from work and costs about $3k.
Even modifications, such as removing the cover from the airbox Vs holes Vs snorkel changes, will affect the INTAKE noise level, which can make a big contribution to the overall dB levels.
I personally wanted improved performance and love the sound of my HMF slip-on, but even if there was no performance gain, I'd keep the HMF because I don't want my KLX to sound like a moped.

Thanks,
Glen

 

Except, as some here have said, that THIS test is for ENTERTAINMENT purposes only; I don't see ANY relevance to real-world conditions. . . . you know, the motorbike under accelleration. I'm not trying to be a killjoy, but who cares how much noise comes out of the exhaust in a static test?

 

OK. . . I see that (in California) a rider MAY be stopped by a Ranger and have his/her bike subjected to a static noise-level test! It WOULD be good to know that your particular bike complies with this "static" test. We have it better, here in WA. state. . . . I've ridden about 3,000 miles over two summers (off-road) and I've seen one Forest Ranger! With a large population (and all the stresses placed on the land) CA. apparently feels the need to legislate/regulate land use more than where I live. . . . too bad. . .

 

Excuse me, What SAE procedure is that ????
Or is this from the Shade-Tree Mechanic book?

 

SAE J1287 is a "Measurement of Exhaust Sound Levels of Stationary Motorcycles". It is meant as a way to measure sound levels from the exhaust only, but would also pick up intake noise, but not the mechanical noise from the drive train -gearbox, chain, tires etc.
The only people who would care are those that put a thread on here asking which systems or slip-ons are the most quiet, because their state or city or who ever regulates noise levels or they personally want to get some better flow and performance, but not get too loud.
If this isn't you, then you probably won't care to look at any threads discussing noise levels. The only benefit to any standard test is so that the testing is done under the same conditions and then those that are interested will be able to compare when they are deciding what they want to change on their KLX.

 

DJFields,
I'm not sure if you are referring to my last post or not but I'm referring to the dirtrider.com article, that was linked by SlapDrum, concerning CA. riders.

 

I find it amusing that some have no clue to the extensive work done in OE automotive / Motorcycle NVH labs to create those noise levels.

Maybe it's best to read the standard linked below as it states "preliminary exhaust noise"


http://ohv.parks.ca.gov/pages/1140/f...287_199807.pdf

 

Not sure what your point is???
That is the test that I referenced and used to get my data and feel that it is a good way to get other db levels for comparison. This standard states that it "can be adapted for a variety of uses, which may include exhaust system certification, enforcement of in-use motorcycle standards and use by motorcycle competition bodies..." In any case this could be a good basic comparison test, unless you or someone has one that they feel is better for all of us to use in comparing systems at different locations.

 

MY point is, your not getting accurate measurements even getting close to a repeatable accurate piece of data. You have too many, and uncontrolable variables not to mention guage calibration.