I remember seeing a post a long time ago and I cant find it now where someone said what you could do to help your bike pass the sound test. Reason Im bringing this up again is my buddy came back from Hollister on Saturday night and told us that he got stopped and taken to the sound test area and his bike didnt pass the first time so he either had to leave or get a ticket. He went back and tuned his pipe(hes got a super trapp I think so its tuneable) and it passed. I will probably be going to hollister sometime soon since the sun is starting to shine again and dont want to run into this problem. One problem with my bike is my pipe is bent right out of the head and I cant fix it, it all lines up right untill I put in the bolt under the gas tank and everything gets out of whack. None of the mounts on the frame or pipe are bent. I know the pipe is bent but I cant see where.

So to get the noise down:
Repack silencer
What else?

What kind of bike do you have? What kind of Muffler? Maybe we can help you.

01 KX250
FMF Gnarly pipe
Turbine Core II Spark arrestor

i wrote a bunch of stuff some time ago. here is what i can remember right now. i'll post more if i remember.

remember all of these things will affect your jetting. so check it!

first thing repack ther muff.

some pipe guards make noise like those spin looking aluminum ones. take it off.

header wrap for hot rods goes a long way for sound but it will rust your pipe prematureley.

take a piece of an old front inner tube and cut a peice off of it and stretch it over the end of your muffler. leave enough extra so that it hangs down. this is good for like 2 decibles sometimes.

partialy close up your air box. by putting the factory removable mud flap thing back on. i have also used duct tape over some of the holes on the air box. remember the bike still needs air and it won't run long if you over do this. sometimes just putting a towel in the bottom of the box will absorb sound.

squish some short pieces of automotive heater hose between the frame and the pipe in various locations. i usually put a zip tie on them as well to hold them on.

air cooled bikes are much louder. use some fuel line inbetween the fins to dampen the vibes. note: don't get crazy. remember this is your means of cooling.

fix all rattles on your bike. levers and plastic. i just use clear rtv to stop the plastic from vibrating. and the levers either fab something creative like using some plastic sheet to shim it or replace them.

look at your bike when it is running. listen to it and find where the noise is comeing from.

a worn out motor will flat make more noise then a new one.





i would say the quickest cheapest way is the inner tube trick, mainley cause you don't have to rejet, but buying a bigger muffler for $$$$$$ is the most reliable and sure way. bolt it on rejet and forget about it. fmf makes a Q muffler that is quieter than that turbine core.

A freshly packed turbine core should pas on your KX. Or go buy an FMF Q

Originally posted by smurfsdad
A freshly packed turbine core should pas on your KX. Or go buy an FMF Q
I had my KX500 (almost new with less than 1 hour on it and new turbine core) with stock pipe tested last weekend at Prairie City and it was at 99.9 db. FMF does not make a Q for the 500 so I'm going to try some of the above ideas.

MY 500 with major engine and ignition mods would not pass even with the q muffler. FMF was easy to deal with for getting my money back since it didnt pass with that muffler. This is my motocross bike so i guess no more hare scrambles till it gets done up with a custom muffler just for hare scrambles to reduce the noise.


And hollister gives you a warning till i believe the beginning of april is what i was told then they begin to give warnings resulting in a ticket after your first warning if i understand it right.There are way too many conflicting stories for me to deal with.

Good luck on quieting it i would go with the Q muffler it lowered mine from 112 dB to 105 dB and i was running a freshly packed turbine core for the 112 it was packed by FMF at one of their sound tests so i know it was good so that one hell of a decrease

i wander if those old plastic body panels that were sold in the late 80's and early 90's (to keep mud off your motor) would help quiet the cylinder noise.

also i bet this new law will start a new line of quiet mufflers.

what ever happened to the "hush puppy" mufflers? those things made bikes whisper.

You might check with http://www.deppipes.com/ They used to make a quiet series muffler. I cannot speak for them personally as I don't have one. It might be worth an e-mail to see if they make the quiet muffler for your bike.