You could always take this approach with your stock muffler.
http://i156.photobucket.com/albums/t.../06KLX250S.jpg

 

didnt you make that out of scrap stuff? i for one dont have scrap stuff or id def do that...its well out of the way of everything...how does it sound?

 

Here is my remade plug. Its for sale too. $40 shipped & comes with FREE muffler

 

That came out really, really nice! But I'm stick'n with my HMF.

 

I think it sounds pretty good. Not too loud or quiet. I cut the muffler down about 7" and made the tip from some scrap mandrel bent tubing.

 

well if you got any more scrap...let me know

 

If you'd like to send me yours plus $40, I'll send you mine. I've been wanting to fool around with another stock muffler. Mostly with taking the inards out and trying some different baffle ideas.

 

This may be a dumb question but isn't the Spark arrestor going to be disabled after drilling?

 

Maybe! But then again statistics show that 99% of forest fires are caused by 1) lightening 2) campfires 3) cigarettes 4) napalm (of course depends on what country you're living in) 5) squirrels playing with matches 6) logging and last but not least, 7) forest rangers. So don't be too hard on yourself.

From www.planetklx.com:

"The long tube of the 11mm (inside diameter) buttplug that goes back into the core of the muffler is approximately 50mm long. The internal piece on the Krizman drawing that is labled "outlet" or the outlet pipe, which extends both inward and outward from the rear baffle, is already in place internally on our KLX exhausts without the buttplug in place -- as long as you haven't gutted the internals. It extends back inward towards the turbine cone approximately 55 mm - actually further in than the pencil sized buttplug tube, making the pencil tube irrelevant for SA purposes. The turbine throws the particles towards the outside, where they have approximately 55mm before they hit the rear baffle and have to turn around and snake back out the large 35mm hole, which - according to the genius of the Krizman design - won't happen. No steeeenking 11mm tube necessary. This confirms that the only reason for the pencil sized buttplug was to lower the sound level to 82dB..."


"Society is like a stew. If you don't keep it stirred up, you get a lot of scum on top." - Ed Abbey

 

What is the reason for going down to 3/8 in the second baffle? Why not stay at 1/2?