How to repack that muffler!

8 replies to this topic
  • Matty05

Posted June 16, 2006 - 03:31 AM


For the benefit of other people that like pictures on how to do things, I to some pics while I repacked my pipe today!

First up, take off the 2 springs that join the muffler to the mid pipe. If your muffler and midpipe are the one piece, take it all off!
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Now that you have the muffler off, take a 5mm drill bit and drill out the pop rivets. If you have Procircuit, leave the one holding the strap together last.
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Take a flat bladed screw driver and tap off the end of the pipe. On the Procircuit, it has got some glue on it, so work around little by little.
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Note that the tip and end cap don't need to be removed!
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This is what you are left with. Pull the core out and remove all the old packing. This is the point you go for latex gloves as fibreglass on your hands is itchy. The procircuit muffler is packed with the "silent sport" stringy stuff, so gloves aren't needed!
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This is the old packing that I got out of my muffler. It is less than a year old! It has had no water in it, I got a bung for it for when I wash it too. Note that it is hard. Not good for noise control or performance.
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Now pull out the core and clean it up with a wire brush!
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This is the stringy stuff packing. Just put it in a little at a time.
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After each time you put some in, get something to pack it down to the bottom. The trick is to put it in evenly, and pack it down evenly. You don't want it too tight, as it won't muffle, or too loose, the muffler will destroy it's self and crack welds. I pack the tip of the muffler a bit more than the front, as this stops the packing migrating down from the front.
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When you are done packing, put the end back on. If you have procircuit, don't forget the strap! I put one pop rivet in completely, then put the other rivets in to line everything up. If you don't, you may have to drill out the rivets and start again.
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You are now done! Just install back on your bike and enjoy the regained performance. Oh, and also it's quieter too!


Posted June 23, 2006 - 04:41 AM


Good one Matty...

I just wanted to add... The exhaust noise level will be affected buy how much and how hard you pack you pipe.

If you Pack it hard... it will be Louder.

If you pack it Lighter and softer.... it'll be quieter.

This is one of those cases where more is not always better.

  • The Duke of Prunes

Posted June 23, 2006 - 05:42 PM


thanks for the tips, this site rocks. I learn something new every visit.

  • AUS_WR450

Posted June 23, 2006 - 06:38 PM



Where in Oz did you get the stringy type packing from? Ballards?

My local places only have the mat type (no pun intended)



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  • Matty05

Posted June 23, 2006 - 06:50 PM


Yeah mate, stringy stuff from ballards, big bag for $20. It is DEP "silent sport" branded.
I used 1/2 a bag for my pipe.

You can get 2 different sizes though, both same stuff. Ask for the big 4 stroke bag!

Went for another blat today, The bike was definately quieter, sounded the same as my missus' 98db GYT-R pipe on her WR250F. Hmmm, might be time to repack that too. Felt like I got some power back too.

  • AUS_WR450

Posted June 23, 2006 - 06:53 PM


Thanks for that. I definitely have to repack the FMF powercore 4. It's got to the stage where even my riding buddy refuses to ride behind me, as he says it is painfully loud!

  • Matty05

Posted June 23, 2006 - 07:01 PM


Well, the packing in these pics is about 8 months old......
People think it lasts forever! I used to repack the 2 stroke every 3 months or so.

  • drewpeacock

Posted June 24, 2006 - 12:55 PM


Good job Matty, now how about a demonstration on checking/adjusting our valves. :excuseme:

  • Matty05

Posted June 25, 2006 - 02:50 AM


Good job Matty, now how about a demonstration on checking/adjusting our valves. :bonk:

Follow your manual! :excuseme: :busted:


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