I have that tip on my KLX300 exhaust. My evaluation is that it is quite loud, but acceptable. It is not nearly as loud as the FMF system, I did a few rides with a guy who had it on his KLX. If I had that exhaust, I would need to wear earplugs for sure...

 

Edit: the other guy exhaust possibly was an HMF (it's easy to confuse between the two) so I'm not sure if I can tell the FMF is louder than the KLX300 exhaust with the alu tip.

 

I have a KLX exhaust on my bike and agree, and think it's rather obnoxious without the end cap.
I experimented with a plate bolted to the end, opening the hole til I found an acceptable sound. I ended up with a thin walled tube, in a homemade end cap.
Tube is 1.35 diameter(was a front fork top out spacer).

 

I installed the HMF turn down end cap on my KLX300 exhaust. Since it is a 3 hole design, you need to drill and tap. However, the sheet metal at the end of the muffler is very thin! I applied some high-temp liquid gasket between the cap and muffler and thread-lock on the bolts, but I am doubtful it will stay attached

 

Maybe you should drill the end cap, not the muffler.

 

I thought about that... but there would be 3 extra holes as the bolt-circle doesn't match between the muffler and HMF cap.

 

I put the HMF end cap on last week. I had to drill three holes in the end of the muffler, and it is simply sheet metal. I had no faith that it would stay, so I put some JB weld on each bolt and hoped for the best. 200 miles of dirt roads later and it's still on there tight. It fits the size of the muffler perfectly, and significantly improves the sound by deflecting it downward. I'm happy.

 

Could do three sheet metal thread inserts and some good thick gasket material or rtv silcone seal Here's a video on doing one with home made installer tool.


I'd be all over that one for what you need. Probably pick up a bag of the inserts at a place like McMaster-Carr or Fastenal for sure, possibly Ace or a big box store. Worth a look.

 

The fmf powerbomb was noticeably quieter on my bike, not a whole lot, but it was noticeable to my ear, great performance boost for me

 

I hole-sawed the OEM cap (putting a cylindrical spacer between the hole-saw and the stock tube end to center it) and then welded in a piece of 1" OD thin wall steel tube. I'd show a picture but the metal was so thin and my welding so bad that I'm ashamed.