Yeah, the M-7 is loud, but it's a good sounding loud. Nice tonal quality I guess you could say.

 

Noise is something I am very concerned about. I've looked around at the various exhausts that are available, but I'm not liking what I see so far in regards to the noise to power gain

Is there any way to use an aftermarket header to increase the flow on the stock 250S while using something like the stock KLX300 muffler/spark arrestor to keep noise at a minimum but still gain some performance?

 

I "hear" a Four Stroke Works header and a stocker 300 silencer will work together, with butt plug removed.
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Is there a mid-pipe involved in that swap? I was considering just going to bike bandit and ordering the header from the 2007 KLX 300 because I heard that would fit.

 

Why!
It's the same as the 250 header, just a little longer and the diameter is a little larger at the muffler end.

 

unless hes talking about an aftermarket one.

And if we're talking about the same thing, no, no mid pipe. Just a header and a can.
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here is what I did.

Exhaust Sound Level Test: 2007 KLX 250S
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Test Standard: SAE J1287

Date: 9/6/08

Method:
-Meter @ outlet elevation.
-At 45 dgree angle from bike centerline and 20" away.
-On black top, no reflective surfaces near.
-Engine in neutral @ 1/2 the 10,500 RPM Redline (5,250 RPM).

Conditions:
-Wind of 0-2mph.
-70 F and 87% Humidity.
-Ambient background level of 42dBA.

Equipment:
-Quest 2800, Type 2 with current calibration and currently calibrated calibrator.
Settings:
-dBA, slow response

Results:
-Totally stock 2007 KLX 250s: 84dBA
-HMF with QC insert: 96dBA
-HMF without QC insert: 98dBA

Note:

1) An 8-10dB increase is perceived by the ear as being twice as loud.
2) These exhausts typically attenuate the higher frequency content and the remaining lower frequency content has a higher energy level and travels a greater distance.
3) The stock pipe indicates 80dBA max, but that is probably a test in an anechoic chamber and other noise sources, such as engine mechanical noise, may have been blocked.

 

If I'm not mistaken the stock exhaust says 88db max, not 80.
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**** Videos

 

If ya want to know how loud your bike is.....................


Let your buddy drive it while you listen........I heard mine f2night for over an entire block.....Maybe 1/2 mile + x 1/2 mile + by a 1/4 +........Sick......I gotta change it....During the winter exhuast echos even worse off the snow...I got the yuck....

Rocco

 

Well since I haven't really found anything I'd consider to be "close to stock" sounding, I guess I'll go with the company that gives me a good deal on the system.

fourstrokeworks quoted me a great price for the complete system, including the quiet tip and green anodized can and threw in a Uni Filter.

Now all I gotta do it get the DJ Jet kit...

So I understand there is some smog equipment on my bike that has hoses running here and there that I have to plug off or something? Can someone link to a post about that? My search skills are seriously lacking in the morning before I have my coffee

I think I'll also get a set of fork springs and a shock spring today too since my forks go down like a hooker on payday everytime I brake.