re-packing exhaust cans

[818Guy]

I'm thinking about buying exhaust cans for my 2006 AE soon. Reading the posts there are comments here and there about having to "pack" them.

Newbie question: what exactly does this mean?

Also, if others can post which ones require packing and those that do not that would be appreciated. Please keep it to Gen II if there are differences.

So far (from my reading) and updated as members post:

Remus = do not have to pack

Holeshot = do have to pack

D&D = ???

Leo Vince = do have to pack

Blueflame = ???

Staintune = do not have to pack

Muzzy = do have to pack

TwoBrothers = do have to pack

 

[madmike2]

IIRC, Staintunes do not require repack. I'd think that most of the aftermarket cans that are lined with fiberglass (glass-packs) would require repack as the glass liner is burned up. Most people don't repack, they just enjoy the increased "volume" (noise level).

 

[Geezer]

Re-packing a muffler means that you take the core out of the muffler, remove any old packing that is left, and wrap the core with new packing. Packing looks like a fiberglass mat and it comes in different density depending on who makes it and how quiet you want it to be. Mufflers that are meant to be re-packed have their end caps mounted with rivets or screws so that you can remove the end caps.

I have a Muzzy muffler and it was very sparsely packed when I got it. On advice from Mike_H I got some Hindle packing and wrapped it as tight as I could. It makes the muffler much quieter than it was when it came from Muzzy. Still loud, but bearable.

 

[Bike Effects]

Leo Vince. Well over two years and 17000 miles. No detectable difference with the quiet cores NOT installed.

 

[818Guy]

Leo Vince. Well over two years and 17000 miles. No detectable difference with the quiet cores NOT installed.

So then they do not need to be re-packed?

 

[madmike2]

Leo Vince. Well over two years and 17000 miles. No detectable difference with the quiet cores NOT installed.

So then they do not need to be re-packed?

Well, trying to decipher and interpret Jeff, technichally they require repacking, however, he's ridden his for 2 years without the aformentioned procedure (repacking).

 

[818Guy]

Thanks. Also updated the list in my initial post.

 

[Shadow]

TwoBrothers need to be repacked

 

[Bike Effects]

Leo Vince. Well over two years and 17000 miles. No detectable difference with the quiet cores NOT installed.

So then they do not need to be re-packed?

Well, trying to decipher and interpret Jeff, technichally they require repacking, however, he's ridden his for 2 years without the aformentioned procedure (repacking).

That is true. I, nor any of my customers that I know of have repacked, but it could be done. I've got 9 years on my Micron slip-on on my R1 and have not ever noticed it getting louder.

 

[818Guy]

Great. Thanks for the info.

 

[HaulinAshe]

How an exhaust is packed/repacked, can substantially change its performance curve.

Generally speaking, a tightly packed 4-stroke exhaust (meaning lots of packing material wrapped tightly) will favor the top-end response, be louder at high RPMs, and detract from the bottom-end torque.

A lightly packed 4-stroke exhaust (meaning little packing wrapped loosely) will favor the bottom-end response, be more quiet at high RPMs, and detract from top-end performance.

The trick is to pack the exhaust for both the note/sound and the performance sweet-spot you desire.

Be sure to use 4-stroke packing material, commonly available at MX shops etc. FMF is a good brand and it looks a bit like wads of fiberglass cloth. You can wrap the packing material with regular masking tape to hold it in place until the final assembly is complete. Some people prefer to use something like safety wire to retain the shape.

Packing is one of the few ways that you can truly affect the performance/torque curve of the typical 4-stroke engine. It has WAY more influence than the average exhaust system change does.

 

[Shadow]

There is no way I would purchase cans that require re-packing, as JeffAshe has said, re-packing cans differently to the way you got them makes a huge difference.

If you have a Power Commander fitted, I think it would be a good idea to run your bike on a dyno after a re-pack.

 

[evil_henchman]

I have no interest in aftermarket mufflers for my FJR but I do repack my dirt bikes from time to time as they have FMF cans. Noise is an issue on offroad bikes in CA and Silent Sport is the only packing that will get my WR426 under the limit. It looks like a bag of string but it really works way better than the factory stuff designed specifically for the can. Cheap and easy too.