Repacking silencer, best material/technique for quietest exhaust note

[Wandell]

My YZ125 and my son's CR125 are both equipped with Pro Circuit pipes and shorty silencers. Both are pretty freakin' loud so I want to try to quieten them down some (before resorting to installing a stock silencer). My question is, what is the best material and technique to use to make the short silencers as quiet as possible? Should I pack it extremely tight or kinda loose? Should I use a particular brand of packing or something like steel wool or fiberglass insulation? Or are they all gonna be pretty close to the same? Or am I wasting my time trying to make a shorty Pro Circuit silencer? Can I even to hope to get it close to the sound level of a stock silencer?

[arnego2]

I use 2 stroke exhaust wool and wrap the entire package in celofane like plastic. It should still be pressable, about 1 to 1.5cm IMO 

[Wandell]

Do you think packing the silencer tighter/fuller helps reduce noise?

[mrjata]

Do you think packing the silencer tighter/fuller helps reduce noise?

Personally, i went for the tight packing.  Make sure that all those little holes are clean and open.  That is huge.  I used the loose material, some like the pillow style and don't like getting fiberglass on their hands, Waaaa...

 

I warped the material with kite string to put into the canister.  worked out well.

[MANIAC998]

Do you think packing the silencer tighter/fuller helps reduce noise?

From what I've been told, the looser the insulation is wrapped, the quieter the exhaust note. But the downside is that it won't last quite as long as having more insulation tightly wrapped.

[Wandell]

Yeah, I've also heard that not packing the silencer so tightly will make it quieter.

[Polar_Bus]

You want to wrap packing as tight as possible. Too loose and the packing will burn and blow out quickly. Use as many layers as you can, wrap masking tape around the outside to hold the packing tight to allow you to insert the core back into your silencer body.

[MANIAC998]

Your typical two stroke is quieter than almost all fourstrokes anyhow, so pack the silencer with as much as you can, and you'll still be quieter than the thumpers, and for longer!!!

[fox007]

If by any chance you have house insulation laying around use it. Its cheap and if you don't like it you can always trash it and get the high priced stuff.  Iv been using it for years. Take thin layers at a time and wrap not to tight but not really lose either, until you have enough to fill the canister. You can use zip ties or wire to hold the wraped insulation as you place it into the silencer canister  Do not wrap tight if you want a quite note from your bike. The tighter the wrap the less it can absorb the exhaust note.