How to reduce the exhaust noise
-
- Posts: 6
- Joined: Thu Jul 12, 2018 8:26 pm
- Location: Denmark
How to reduce the exhaust noise
My AJS 18 CS from 57 is making a lot of exhaust noise (as it should) - but if possible -i would like to reduce it. I have seen some headers for 18S where the end of the header is blocked and instead there is a lot of holes around the area / diameter stiching in to the muffler. Does this this have a significant effect on the noise as well as the performance or is it an acceptable solution. If so i could easy modify my competition header to same design since around 120 mm af the header already is sticking into the muffler.
Anyone having experience with this type of header
BR Per
Anyone having experience with this type of header
BR Per
- Rob Harknett
- Member
- Posts: 11236
- Joined: Mon Jan 01, 1990 12:00 am
- Location: ESSEX UK
Re: How to reduce the exhaust noise
I believe original pipes that had the end blocked, were such, as this was the baffle. Repro's have a shorter straight through pipe with baffle in the silencer. Having both will not allow gases to escape properly, back pressure will effect performance. If you have a clean engine and new exhaust, the bike may sound noisy. It will quieten quite a bit when the system get's a bit of carbon build up. Which again should be kept clean to avoid back pressure. Although you do not get so much carbon build up with todays cleaner fuels, compared to back in the 50's era. An engine decoke and cleaning exhaust with caustic soda hardly ever needed. Due to cleaner fuel and lower mileage.
- clanger9
- Posts: 1165
- Joined: Sat Jun 20, 2015 9:38 am
- Location: Chester, UK
Re: How to reduce the exhaust noise
A "pepper pot" header will be quieter than a straight-cut header. The perforations allow the the pressure pulse into the silencer more gradually, which takes some of the loud crackle off.
As long as the end of the header is open at the end, it shouldn't affect performance.
As long as the end of the header is open at the end, it shouldn't affect performance.
1989 Moto Morini Dart 350
1993 Ducati 750SS
1993 Ducati 750SS
-
- Posts: 6
- Joined: Thu Jul 12, 2018 8:26 pm
- Location: Denmark
Re: How to reduce the exhaust noise
Thanks a lot for the feedback
Since my muffler is very open (not much restriction - if any) i think i will try with the "pepper pot" modification
as mentioned - it migth not even be needed to block the end of the pipe
Since my muffler is very open (not much restriction - if any) i think i will try with the "pepper pot" modification
as mentioned - it migth not even be needed to block the end of the pipe
-
- Member
- Posts: 1439
- Joined: Sat Oct 09, 2010 9:17 pm
- Location: ABERTAWE UK
Re: How to reduce the exhaust noise
only dead fish go with the flow
-
- Posts: 6
- Joined: Thu Jul 12, 2018 8:26 pm
- Location: Denmark
Re: How to reduce the exhaust noise
Absoluty - its give me a clear picture what to do. - only one quistion - the header open at the end - rigth ?
-
- Member
- Posts: 1439
- Joined: Sat Oct 09, 2010 9:17 pm
- Location: ABERTAWE UK
Re: How to reduce the exhaust noise
If the header is the exhaust pipe, then the end is closed off and the gasses can only get into the silencer through the series of sixteen 8mm holes.
The new exhaust system I put on my G80cs from Feked is very loud, the exhaust pipe doesn't have the pepper pot set up but I may alter it in the winter.
Colin
The new exhaust system I put on my G80cs from Feked is very loud, the exhaust pipe doesn't have the pepper pot set up but I may alter it in the winter.
Colin
only dead fish go with the flow
-
- Posts: 6
- Joined: Thu Jul 12, 2018 8:26 pm
- Location: Denmark
Re: How to reduce the exhaust noise
Okay - i see - since my muffler is open i will block the end of the pipe and drill 16 Ø8mm holes similar to the picture.
Thanks again for information / BR Per
Thanks again for information / BR Per
-
- Posts: 2886
- Joined: Mon Mar 24, 2014 5:44 pm
- Location: Aberdeenshire
Re: How to reduce the exhaust noise
Hi
The area of 16 x 8mm holes equates to a pipe diameter of around 1 - 1/4" - seems a little restrictive.
I know the parts list illustrations are not 'gospel' but they show more holes - they also seem to indicate the pipe is not closed.
Perhaps it may be good to drill some holes and see how they affect the noise output rather than plugging the pipe straight away.
Regards Mick
The area of 16 x 8mm holes equates to a pipe diameter of around 1 - 1/4" - seems a little restrictive.
I know the parts list illustrations are not 'gospel' but they show more holes - they also seem to indicate the pipe is not closed.
Perhaps it may be good to drill some holes and see how they affect the noise output rather than plugging the pipe straight away.
Regards Mick
- ajscomboman
- Member
- Posts: 3971
- Joined: Mon Jan 01, 1990 12:00 am
- Location: HAMPSHIRE UK
Re: How to reduce the exhaust noise
Interesting subject, I'm just about to go the opposite way. The original pipe for a 56 CS is 42" long straight through with no restriction. My current setup is the same 42" pipe with a silencer on. This seriously restricts the breathing even after I've removed the end baffle. The pipe extends into the silencer 4-5" and restricts the breathing where it nearly contacts the inner baffles to the extent where the bike will not pull full power from 3/4 throttle upwards. The carb setting is fine so I'm sticking with the silencer but cutting the pipe so it just pokes into the silencer enough to clamp securely, and I love the noise!