quieter silencer?

[jmics19067]

I have an older mx bike that I mostly trail ride. It appears I can add approximately 2" of perforated core, packing material, and canister towards the expansion chamber. Now if I modify my existing silencer or make a new one that would have this approximate 2" more silencing area and yet would be the same overall length,<stinger to end cap> would /could I have a significantly quieter bike with out a drastic tuning/power change? I am not to concerned about revs building slow or losing top end a little if I have a quieter bike. Provided the amount of quiet is greater than the affect of horsepower.

Also what is the purpose of oval canisters? If I have to resort to making a complete silencer from scratch what would be the problems of a round canister compared to oval? Is it just so you can fit in more packing material without having to cram it in?

what would be the downfall of having a longer silencer out of the back? I have an aftermarket silencer/sparkarrestor so this thing is pretty long as it is but still not quiet enough for my likings. I have tried repacking with the stuff the silencer manufacture recommends , silent sport and house insulation but nothing is tickling my fancy yet.

any replies and ideas would be greatly appreciated
thanks

 

[SFO]

Hooey!
Making quiet is as much derived from testing methods as it is subjective "ear" noise.
Really, hear (sic) in Norcal we are being tested in all the state riding areas.
The results are nebulous and spurious in my HO untill we establish a real and consistent testing method.
Bill

 

[Lorin]

I did a similar thing with my stock silencer on my bike. It came with a two section silencer (not a spark arrestor), where the back section was basically just a tube with a hole in the bottom for spooge to drain into. I ended up drilling holes in the back section and packing the last three inches with additional packing. In addition, I had a local muffler shop tack weld on a spout to point the exhaust note toward the ground. Both helped quiet the bike down a little and I noticed no differences in power delivery. I think the downspout helped as much as the extra packing did. I also wrapped the first 4 inches of the silecer pipe (before entering the silencer) with inner tube and safety wire to 1) provide additional seal, and 2) to provide a little extra damping.

 

[jmics19067]

Thanks for the replies

Lorin thanks for confirming what I hoped and the inner tube rubber band trick. Now I guess I have to go and make a silencer and try it out.

 

[cujet]

I built a stealth silencer for a CR500 that really worked. It took time and is a little heavy, however the weight issue could be addressed. My design used 3 chambers and 2 perforated cores. Try a search for my post. I also posted pictures on macdizzy.com bulletim board.

Chris

 

[jmics19067]

great thank you!!!!

 

[1999RM125]

I have a question here, i am gonan repack my silencer as i just got my fatty in the mail, although i cant ride it yet(motor is at a shop like 45 mins away getting the tranny fixed) i can repack the silencer, if i understand correctly, if i jam pack as much as i can into the silencer will it be louder or quieter, im looking for quieter, so should i cram until my fingers bleed, or loosely pack it in there to get the quietest possible (BTW its a stock silencer)

 

[marcusgunby]

Somewhere inbetween-not tight but not loose.

 

[1999RM125]

what would happen if i packed it to tight ot too loose?

 

[marcusgunby]

not alot-too loose and it will blow out quicker-too tight and it will actually be louder than too loose.

 

[1999RM125]

ok, thnx for your help