I have a Powercore 4 only my KLX and although it looks great and performs nicely the damn thing is just too loud. Ive heard a Q4 and its not much quieter.

I took my bike to Jones Lake state park Sunday just to putt around and got dirty looks from the park official I past by. If I had hung around I know there would have been something said about it.

I had a Cobra exhaust on my XR250R back in the day and that thing was just as quiet as the stock KLX muffler.(they dont make dirt bike slip ons anymore)

OH and puting on the old stocker is something I dont want to do

Got any ideas guys?

 

Try the 2Bros M7 with a P1X tip

 

I have an 09 with an HMF slipon, Quiet Core and Spark arrestor. I don't consider it quiet. I have a friend with a KLX400 and an FMF...that bike is quieter than mine. Is that a function of the FMF vs the HMF, or, something different about those two engines? I don't know...but mine is definitely louder.

When putting around gently, I consider mine to be quiet enough. Wide Open, it's loud.

Is there a quieter core offered? Could you weld a ventilated tube inside it, forcing gas through it before it exited?

Guess I didn't help much....sorry...

 

I was actually thinking of making my own silencer somehow or modifying one thats supposed to fit another muffler to work.

Cruising down the highway at 7K rpm my bike is pretty damn loud by any standard. I drove about 50 miles non stop last weekend and the volume was getting old after a while.

 

klx300 exhaust with stock tip on when you want to be quiet, off when you want the performance/sound. I think the stock 300 tip is too restrictive, so i made my own from a cutout of the stock 250 exhaust. looks like stock, and works pretty good.

 

I don't know but my FMF q4 is very quiet.
Possibly the one you heard was old and needs to be repacked?
i just went through a tech inspection and they wrote 66db on my entry.
i don't remember what rpm it was checked at though.

 

66db?! Was it running?

 

If you can either get a Supertrapp system or weld on a Supertrapp tip to a system you can use the discs to adjust for noise. I have a 4" Supertrapp tipped exhaust, which is running 10 discs and is reasonable. I'd think that due to the reduced exhaust volume (quantity, not sound) of a 250 a set up like this on a pipe could use as little as maybe 6 discs which would quiet things down appreciably. Seat of the pants will tell you where the optimum is in general. Too much restriction reduces top end performance in any given gear, but will help lower range. Too free of flow will reduce bottom end to an extent.

If your present system is round and big enough you can buy a weld on tip or something like that from a shop or on-line. Go to a site like Parts Unlimited and check out their sections on Supertrapp both for street or dirt. They make caps and cannister tips for universal fit.

 

Are you looking at the entry up side down? LOL My Q4 was checked last year and it was 99db. I will say that I don't think those guys knew what they were doing when they checked it. I was surprised that it registered that high.

I think the Q4 is about the quietest aftermarket muffler out there. I wouldn't call it quiet,but relatively speaking it's quieter than most. It is engineered to be under 96db when properly maintained. The dirty look you thought you got, may have been imagined, or may have been because the guy thought you were riding a real dirt bike on the road illegally.

 

the club knew what they were doing as they had 2x4's laid out and another running at a 45* to the bike. they used a measuring device that they held on the handlebar and it told them the RPM. So here is what happened: they asked me what size the bike was, i said 250 of course, they looked at a sheet and determined what RPM i should be checked at. they held their little device onto the handlebar and revved the motor until it was at the determined RPM and held it there. The guy out back held his measuring stick on the end of the pipe to determine the exact distance and at 45* from the outlet. He handed me the sheet with a 66 on it and i said thank you very much!!!!!!
The process seamed very scientific and it only revved about 2500 - 3000 at most.
I guess there is a standard method of measurement for AMA events.