Silencer Too Loud

[jackstringer]

I have seen people put brillo pads in also wire wool also works. Usually last just long enough to get past scrutineering or MOT. After a short wile it gets hot and burns out or just gets thrown out by the exhaust pressure.

Jack

[Merlin]

We used the old Brilo pads worked for quite a while if you kept the revs down,

[Don Madden]

I will try to explain the AMC baffling, (?) system a little better, pun intended. The pipe is long enough to reach about the center of the silencer, has a welded cap & holes or slots near the end perforated in the sides. The silencer has a bulkhead with a central hole as large as the pipe welded a distance to the rear of the pipe end. The gasses are forced out of the holes into the chamber created changing direction 90d. They then change direction again, flowing to rear & find their way out the hole in the bulkhead. The directional changes & expansion of the gasses, as in other silencers, cause the gasses to diffuse, reducing the sharp pulses which mellows out the sound. Quiet silencers have more perforated tubes & bulkheads to smooth the gas flow more & some have the adsorption material as well.

To work, your pipe must be capped & long enough to extend into the chamber before the bulkhead with enough length to have sufficient holes of sufficient size as not to restrict flow. The silencer must have a bulkhead with a central hole large enough to not impede flow & positioned far enough from the end of the pipe. Only you have the parts on hand to probe them & find if they can be modified to work properly.

Cheers, Don.

[moley]

What about buying a mute from Armours ? you tap it into the end of the pipe and it a cylinde with holes all round it and the end blacked off. I think Armours do them in general for Megas ( Because of the row !!) but i have used on several bikes... i would advise glueing them in pipe as if you pot rivet the silencer is a pain to get on and if you just bang in the end they sometimes come out ( How do i know that...twice)... there are £8.50 each...definaltely quietens the exhaust note down!

[Eric]

My silencers are megaphone probably from Armours as they are not original. They have pepper pots in the end but the neighbours still complained about the noise (justifiably) so I converted the pipe to reflect the original idea with much improvement. I knew there could be holes or slots and decided the area of them must be a little larger than the area of the pipe. Since then after drilling lots and lots of small holes I found that one original spec was four rows of four holes 7/16" dia each row at 90 degrees to the other and each rows hole centres in the middle of its adjacent row, spread over about 3 1/2" to 4" the open end of the pipe is just capped off. That's for a 500 twin bigger engines may need bigger holes, just keep the total area bigger than the pipe area its amazing how many holes you need to do that.

[DWS]

Hi Don

Thanks for that however, and I quote from your comments "The pipe is long enough to reach about the center of the silencer"

In the new Silencer I have from Feked the welded in baffles are only about two or three inches inside the body of the silencer from the 'Input' end so not much of the end of the pipe goes into the silencer making it difficult to modify the end with holes etc. I Guess a metal baffle tapped into the end of the pipe, as long as it doesn't protrude too much, it might be the only solution here

[Eric]

Tell Feked the silencer cannot be fitted to a standard existing exhaust pipe and see what they say. But if it does not go in how have you been running the bike to determine its too loud?

[jackstringer]

DWS,

Could we have a pic of the offending exhaust.


Jack

[TommoT]

I did this to quiten my own exhaust from Armours:

Drilled exhaust pipe

End of pipe is welded shut. But I drilled 1/4" hole in the middle of the disk, and fitted a bolt. This left me with the option of opening up this hole, if the rest of the setup was too restrictive. Btw. the number of holes approx distance was copied from an original baffle. Only thing to watch out for is not to drill a hole pointing directly on the sidewall of the silencer that can be seen from the side. This can cause blueing. (Don't ask how I know!).Edited by - TommoT on 06 Jun 2010 3:30:57 PM

[DWS]

Eric

To fit the new silencer I had remove a good 4 or 5 inches off the end of my existing pipe (aftermarket - make unknown) so that it slid on far enough for the stud on the silencer body lined up with the mounting bracket on the chain rail.

As for contacting Feked, they are closed for their summer holiday right now but as soon as they are open again I intend to contact them about this.