I'd like to findabetter breathing exhaust that's relatively quiet as well. How is the stock KLX300 w/ butt plug removed?

Mark, I'm tempted todrill out the stock KLX exhaust but I'm thinking that would negateit's spark arresting abilities. Does anyone know if the spark arrestor is affected by drillingthe stock muffler?

 

No it will not mess with the spark arrestor, so go for it. There is also a post of someone totally dismembering there stock KLX muffler to see what's inside-very insightful!

 

KC, you took the words right out of my mouth!

 

I thought the consensus was that drilling DOES affect spark arresting capability.
A spark arrestor must be in the final few inches of the can - it's not down deep.
That would negate it's function (to capture burning embers of soot, carbon, exhaust packing, etc).

When they test the bikes at a racing event for spark arrestors, they stick a short rod in the muffler to feel for the screen.

 

Ok so! Do any of you have a stock exhaust you would like to part with so that I could play mad scientist with.

 

I would stick with the stock exhaust if it were me, and make up the torque with gearing. The HMF is definitly louder than the stock exhaust. It is also not just the db. rating that makes how loud an exhaust sounds. Take two exhausts with the same db. rating, one has a higher or lower pitch than the other. One of those exhausts will sound louder than the other to the human ear and/or carry different due to the different tone it produces. There was a member on here that traded a full muzzy system straight up for a stock exhaust because he needed to run stealth.

 

It's been done already (mad scientist with stock exhaust), check out: https://www.kawasakiforums.com/m_192966/tm.htm

 

If you want to stay quiet, just keep the original exhaust..I drilled mine out and it is louder and carries a lower tone..the lower the tone, the further sound will carry due to the wavelength...that's why you can hear these cars/trucks with loud stereos coming from far away is because of the sub-woofers that carry the bass (lower tones)

 

+1. Thelower frequency (longer wavelength), will carry much furtherthan ahigher (shorther) one. The fact that they have thesameSPLmeasured ata very short distance from the muffler means nothing. Among the aftermarket systemsavailable, the FMF Q4 slip-on is themost quiet, butit's still noticably louder than stock.

 

We were all laughing at work yesterday when this guy on a Harley idled up. It had a deep throaty harsh rumble that set off all the car alarms. Inside the building we were in it was still obnoxious. I guess his hearingis so bad he had to really turn up the volume so HE could still hear it.