So, after running my bike with the Emgo Shorty, I decided that as much as I loved the sound, it was just a tad too loud. My mission is to muffle it by 10 to 15% only.

First thing I did was take off the Shorty muffler from my bike.

The end cap is screwed on by three screws. Unscrew those and then try to pull the end off. I couldn't pull it off with my hands. I finally used the end of a wooden hammer. I stuck it in the end there and gently pried it off. Was actually easy this way.

Next comes the baffle itself. This thing does not want to come out easily. But if you stick a screw driven in the narrow end, and then rest it on the little edge of the baffle, then hammer it hard a few times, the baffle comes loose.

Here's what it looked like when I pulled it out! This is a brand new muffler, ridden one time!  



Next I decided I'd experiment with adding something to the baffle, to perhaps create a little more back pressure, and maybe dampen the sound just a little. I read somewhere else that people have put sink crumb catchers on the ends with mild success. I went for the huge stainless washer ( way cheaper ) and I spaced it out with nuts and washers. Air can flow around the side and through the middle. If it needs more flow, I can either drill holes in the washer, or I can space it out more. Or I can just remove it and the holes will stay patched by the bolts.



Next I picked up some proper material from a local bike shop. Was only 6.95 for the pro stuff. Then I wrapped it up with tape first, and then wire ( removed the tape ).



Now just work it back into the muffler, being careful to push the wire through the inner lip. Takes some patience.

Tip: Wear gloves when handling the fiberglass stuff.



And there you have it. A properly packed muffler! Now to get it on the bike and determine if it has actually lowered the volume or not.
Stay tuned...

justin_o_guy2 wrote on 08/08/11 at 22:23:32:



You did two changes at the same time.  I'd like to hear what it sounds like with each change by itself, before using them together.

IOW, what does it sound like with the proper insulation and no washer?,... and what does it sound like with the washer but no insulation,... THEN, both changes together.

Fiberglass insulation either burns up and disintegrates right away, or soon thereafter, or some time after that.  They just don't make any stuffing that lasts very long for our kind of situation where, under full throttle, the exhaust is REALLY hot and pulsing like crazy.

You might try using stainless steel packing,... the stuff they use for kitchen scrubbing.  It's a bit of a gamble because the alloy they use for that varies widely.  Get a few packs at Walmart, etc.  Cheap.

drums1 wrote on 08/09/11 at 05:23:14:



The stainless steel scrubber stuff doesn't work very well unless you fill in just about all of the volume of the chamber it is in.  For example, in this Emgo Shorty muffler, the fiberglass (stock and mmosel's repack) filled in much less than the whole volume.  If the scrubber stuff were installed that way, I doubt it would make much diff either.  In any event, the stainless scrubber stuff won't absorb as much sound as the fiberglass,.. but it usually won't vaporize fairly soon like fiberglass and steel wool.

Yeah, not sure how long this new packing will last. Some people have reported 4000 miles on their bikes, but that naturally will vary bike to bike. There is also some stainless steal wool packing out there that I might try later on.

Here's one on ebay:
http://cgi.ebay.com/ebaymotors/Stainless-Steel-Muffler-Packing-Exhaust-Silenc...

This next link looks pretty good:

http://www.amazon.com/Two-Brothers-Racing-Stainless-005-10038S/dp/B000WKFNY6

Also, I know I did two mods at once. And that does make it hard to know exactly what is doing what to the sound. But I didn't feeling like redoing it 4 times, so I just took a chance and went for both. I'm going to go start it up in just a bit.

OR maybe ceramic wool is the ticket?
http://www.youtube.com/watch?v=LEsLktGzNx8

Success!!!!!

I just fired it up and it sounds super tight and very sporty, without being obnoxious. I think I changed the sound and muffled it by 15 to 20%.

It is true though, that I don't know exactly how much the washer is doing. If the fiberglass burns out over time, then I'll probably notice a difference in volume, and I'll then be able to tell exactly how much the washer is doing. I could take off the washer, but I'm too lazy and I'm super happy with the sound. Maybe I can record it.

This is also the first time I've run it with the new k&n air filter (drop in ). I'm gonna go take a short ride downtown now and see how she runs.

All good tips and feedback!

WD, good stuff. Although I think I'd rather deal with ceramic than asbestos.

I might at some point experiment with adding something down the other end of the pipe for kicks.

Yeah I've been looking for some cheap stainless mesh screen. Haven't found much available yet. There are a few small pieces on Ebay, but it seems pricey. I'd like to find a cheap source for the stuff.

I just had a look at the insides of our mufflers for the Double RYCA Build.  

Pathetic.

The fiberglass in there looks like it'll be about as effective and durable as toilet paper.





I'll be checking out some of the sources you guys mentioned for more durable and sound-deadening stuffing.