Muzzy Exhaust
How much difference does the Muzzy exhaust system make?
I have just finished installing my second Muzzy system. The entire system weighs just 5 1/2 lbs on my bathroom scale. The stock mufflers alone weighed 13 1/2 lbs. I didn't weigh the headpipes and centerstand but it's a few pounds more off the bike as well. The stainless steel head pipe looks great and fits perfectly. You can search the Ninja 250 board for installation tips if you need them. Less weight + more power = faster, better-handling bike.
The Muzzy is loud, but it has a deep tone; I don't think it is obnoxious. A good helmet keeps most of the noise out. Oil filter and drain plug access is fine.
Do I have to remove the centerstand to install a Muzzy exhaust?
Understandably, most people want to keep their centerstand when they put on a Muzzy system. Centerstands are very useful.
There are a few problems with this, however. First, the spring that holds the stand in place when retracted rubs the Muzzy's larger head pipe.
Second, there is no "stop" for the stand anymore when retracted (since the left canister is gone); there is nothing to keep the spring from pulling the centerstand up into the swing arm and drivechain. You could possibly fabricate a bracket to hold it in place, but it would involve some skill and is not a standard mod, so there isn't much information about it.
Lastly, the Muzzy is designed to increase performance a bit, sound good, and look good. One way it looks good is by really cleaning up the back of the bike; with the stock exhaust cans gone the swing arm is fully visible. If you leave the centerstand on, it will be quite an eyesore.
Without meaning to discourage anyone from trying, it's probably more trouble than it's worth to keep it. You can buy a nice swingarm stand for about $70-100 though, which will let you do most of the maintenance the centerstand allows. The only time you'll probably still use the centerstand is when you're doing rear suspension work; the stand can be loosely attached temporarily with two 17mm bolts, and put back in the parts bin when the work is done.
How do I repack the Muzzy?
There is a kit available from Muzzys for repacking the insulation material in your muffler. It's about $25. You'll need a pop rivet tool (about $10) and rivets (1/8" diameter, ~3/8" length) to put it all back together. The end caps are stainless steel and are reused.
The repair kit consists of the perforated inner tube wrapped in fiberglass. If you could get the right fiberglass material from a muffler shop or auto parts store, there is no reason you couldn't just replace this bit. Look for material for automotive glass pack mufflers.
What you'll most likely see when you open up the can is that what little fiberglass is left in it has settled to the bottom half, so there is no sound absorbing material at all in the top half. (And you were wondering why it was so loud.) With the new packing, the bike should be quite a bit quieter than it was. Still loud, but tolerable.
To install this, you have to drill out the rivets and remove the end cap (sounds simple, but it's awkward and takes a bit of effort. One member recommended seeing if Muzzy would do this for you.)
Only one end cap needs to come off, and the engine side cap is easier to get off, since the mounting hardware provides something to pull on.