Thoughts on loud exuast !?

[CATSLEDMAN1]

4 stroke and 4 times as noisy

the sad situation is most sno bikes are 4 stroke. at a distance a quiet 4 stroke is louder than an unmuffled 2 stroke.

the thunderous echo across a canyon of a stock climbing 4 stoke sled is almost funny, a sled going no where next to a couple of sleds that make no noise railing past. the single 4 stroke sno bikes are almost worse than a 4 cyl 4 stroke gp sounding sled.

looking out across the valley we ride in last year, 20 sleds or so playing, but the unmistakable sound of two climbing kx450's, stock exhaust grinding on a hill dominated the faint distant fuzzy buzz of the two stroke sleds. at the distance couldn't barely hear any of the cats and Polaris's with cans and turbos, mile and a half away those two kx's had everyones attention.

not good, taint going to make us anymore popular with other backcountry groups.

 

[Chadx]

I've noticed the same thing in the summer as four stroke bikes became more common in the mountains (starting around 2000). Four stroke sound just carries way further than 2 stroke. Kind of a shame because I've always preferred 4 strokes. One more reason to be extra conscious of ones choice of exhaust. Even spending the extra coin to replace a stock exhaust with a quieter aftermarket exhaust. Seems there are more and more willing to do that than replace with a louder aftermarket, which is nice to see.

I just got a mountainhorse kit this fall and will be bolting it up to a 2004 KTM 525 that I also bought this fall. It has stock exhaust which is plenty loud I noticed when trail riding before the snow flew. Not as loud as some, since it's an EXC, but really loud when compared to all of my other dual sport bikes. I'll be trying to find out stock decibel rating to determine if it's worth looking at aftermarket exhaust that is quieter.

Hopefully some day there will be a market for much quieter exhaust that still makes stock power (I'm talking quiter than the FMF Q series). Unfortunatly, the demand isn't there. It can be done but the penalty is cannister volume (and corresponding weight). Not many are willing to take the weight hit and ride around with an exhaust can the size if some of the large units on multicylinder street bikes. It would be interesting to see how quiet one of our race thumpers can be made (undersanding that there would still be a lot of noise from intake and from mechanical sources).

Anyone cooking up any experiments? Like running dual cans? or running street bike exhaust? etc.

 

[1dn5up]

When I raced supermoto agianst sportbikes there was a 89Db sound limit my bike did ok some of the other sumos with stock pipes didnt so they ran a machine gun style silencer wired to the end of the pipe did the trick.

basicly 6"long pipe with a ton of holes drilled in it

 

[CATSLEDMAN1]

pointed down

I like the idea of exhaust pointed at the ground like the sleds. Our bike exhaust being up and pointed at the horizon is likely a lot of what carries sound and makes for a loud sno bike.

 

[wellfed777]

great points all

so lets compile a list of the quietest exhaust kits or quiet tips avalible so folks can be in the know

let it snow

 

[Moto4Life]

Don't they make some funny silencers that look like fins on the end cap to be really quite for hunting. If you are really wanting to quite it up I think they are REALLY quite for the most part. Might have just been for wheelers though not sure.

Im happy with my 250fs stock db, not sure what it is but it does not seem to bad. Makes all of the other bikes on the track seem like straight pipes. I listen to my music so with the mix of the two I can hear my bike just enough to know what its doing and appreciate the beauty and listen to tunes at the same time(my happy place). I think in those big bowls though its much loader, we have a track here called the fossil bowl and when someone is climbing the hill, it echos like no other.

 

[M5-]

I just repacked my muffler on my KTM, not really my favorite job but it does knock the noise down. The packing doesn't really last very long in any pipe, they all just get progressively louder, it kinda sneaks up on you, next thing you know your bike is WAY loud. I'm going to try and repack it more regularly.

M5

 

[Cberg]

great points all

so lets compile a list of the quietest exhaust kits or quiet tips avalible so folks can be in the know

let it snow

Anyone have an exhaust to put on the list?

I rode this weekend and have decided I am definitely getting a new slip on. My bike is a 2010 KTM 450 SXF, I am leaning towards something like the FMF Q4, does anyone know of a quieter one??

PS, Two Brothers is NOT on the list of a quiet slip on....

 

[warreng417]

I tried a db dawg insert on a street legal yz450. It took the crackle away but was still loud. Q4's are a bit quieter but dont kid yourself, its still loud.

 

[Cberg]

I know all 4 strokes are loud but there are pipes that are not as loud and a tone that is less abrupt.