I have an HMF on my 450 and i am goin on a ride where a loud quad isnt aloud. I have the stock exaust still but i was just wondering if by putting a spark arrester in it will quiet it down and how much? Thanks for the help.

Cody

 

I've got an 05 YFZ with a HMF and know all too well what you mean about the noise. I added the quite core from HMF to it but it's still very loud even with that.
I ended up taking a small piece of metal screen and wired it into the front of the quite core insert where it goes into the pipe. This helped dramatically. I was worried it may have given it too much resistance and back pressure but I've been running it like that for 2 years now and no problems whatsoever. It's still loud but no where near the level of running the quite core alone.

 

Just the sparky does nothing. The quiet core gets my '05 down to around 99/100dB.

 

So then probably the easiest thing to do would be to put the stocker back on for the weekend.

 

Yeah, if you need to be quiet that is what to do. I had the exact same situation. Bought a Lexx slip on from Rocky Mountain. With the quite core it was 94 and the power was closer to the HMF than it was stock. I didn't have to rejet either(although it was running a touch rich.)