OEM Mufflers: What's inside?

[Mr. BR]

Hey FJR lovers,

Since I had no takers for my free OEM Mufflers with the "trooper mod", I decided to cut one of them apart just to see what's inside them before I toss them in the recycle bin. First I had to hit the local Harbor Freight for a pneumatic cut-off tool and some 3" wheels... it worked ok but I need a better air compressor. Anyway, here are a few pictures:

Outer skin removed revealing ~1/4" of fiberglass (?) insulation and mesh:



After removing the insulation, you can see the inner core of the muffler:





Next, I removed the perforated sections revealing the guts:





And finally, here is the exhaust flow through the muffler. There are three distinct and separate chambers:



It's easy to see why these things are so heavy!

Regards,

Mr. BR

 

[Redfish Hunter]

Well done! I often wondered. I love to see a post like that, showing actual work. Good Stuff.

I see your bike is a Gen1. You have to be careful with the Gen2 mufflers. I heard there were some cats or kittens or something in there...

 

[PhilJet09]

Interesting. So, after 72,000 miles I've noticed my bike is a bit louder than new. I guess the fiberglass breaks down a bit over time?

 

[escapefjrtist]

Thanks for the research work! I can see now how some have shortened them and made a two chamber can...

--G

 

[Pterodactyl]

Interesting... thanks. And to think, I was just about to offer you a couple of hundred dollars for them.

 

[Twigg]

A very clear demonstration of how the "back pressure" builds in the exhaust. The fueling and timing of the engine is dependent on that relationship, and this shows how it can be affected by "straight-through" pipes.

 

[ahchiu]

Nice post.

 

[supertankerm60a3]

Great info, the way those resonance chambers are laid out is really enlightening.

 

[Mihalis fjr]

Very interesting!

Thanks for sharing

 

[FJRMGM]

finished reading the internet and too much time on your hands bunky??

 

[Big Sky]

So, Mr. BR, how do they sound now that you've "opened them up a bit"? Is this now to be henceforth and officially known as the "BR Mod"? The "BR-R-R-A-A-A-P-P-P Mod"?

 

[Mr. BR]

So, Mr. BR, how do they sound now that you've "opened them up a bit"? Is this now to be henceforth and officially known as the "BR Mod"? The "BR-R-R-A-A-A-P-P-P Mod"?

LOL! I hope not.... they only sounds these lumps will be making is when I toss them in the recycle bin! The "trooper" mode was not THAT loud but still more than I liked as I depart for work each day before 7am with kids and neighbors still asleep....so they had to go. My '05 is now sporting a nearly new set of GEN2 mufflers courtesy of another member and they are fabulously quiet!

Now I'm riding a GEN1.5.....

Regards,

Mr. BR