Can anyone recommend a good pattern silencer that is not tooooo loud!!
I rebuilt my B40 a couple of years ago and bought a silencer from one of the usual dealers but it is very loud.
I've tried to put up with it but feel it needs changing. Tried one of those moderators stuck up the end of it and it made minimal difference.
The original silencer sounded really good but was past salvation.
As far as I was aware, the silencers you can get for the C15 and B40 are basically of a similar pattern and I would not describe any of mine as being loud. Have you tried comparing yours with the many examples you can find on YouTube?
It is noisy!
A mate of mine in our village has a C15 and that sounds far more civilised!
The pattern silencer is noisy - the original one was so much better!
I've got an old B40 silencer in very good condition that you are welcome to try - which part of the world do you live?
I purchased my fully restored '61 B40 last year and thought at the time that the exhaust was on the noisy side but just accepted it as is. Earlier this year I needed to remove the complete exhaust assembly to remove the RH engine cover to check the small oil drainback 1/16 hole was not blocked.
After re-assembling and refitting the exhaust, for some reason the exhaust sounded much quieter and more 'normal' ! There was no previous evidence that the exhaust (which was new) had originally been wrongly fitted. However when refitting, I felt the exhaust needed a bit of a push to fit fully back into the exhaust port so maybe it hadn't quite seated properly when originally fitted.
Good luck and I hope the decibels reduce for you !
I've never really understood how BSA managed to get away with a push fit of the exhaust pipe into the cylinder head. Most times this works ok but occasionally it can leak badly! However, it should be relatively easier to tell where the exhaust noise is coming from as you ride along especially since the noise from the silencer is normally very distinctive!
I think the reason modern repro exhaust systems on cars and bikes are noisy is two fold, firstly thinner metal and secondly not enough baffling. We used to make gun silencers and it was an art balancing weight and sound deadening. It's probably easier to use flat surfaces than concave or convex surfaces for the baffles. Short of cutting an old and new up its not easy to tell.
As for the pipe fit in the head, is there exhaust rings fitted that would cause the pipe to swell and fit tighter. It's when the ring does not allow the pipe to swell enough due to bore in the head being worn that causes the problem.
Another problem is too efficient baffles causing back pressure building up and the head and pipe joint is the weak point.
The BSA B40 was essentially a larger capacity C15 engine which itself was based on the earlier Triumph T20 Tiger Cub engine. The Triumph approach was to incorporate a short exhaust stub that screwed into the head over which the exhaust downpipe fitted to be held in place by a finned clamp. The earliest C15 used the same method. However, the later models and the B40 dispensed with the exhaust stub and teh exhaust pipe became just a push fit into the head (albeit fairly snug) with the finned clamp now being purely for show. The fitting did not include a gasket such as a copper seal. Most of the time this arrangement works fine.
Hi
I'm located just off junction 11 of the M42.
I think I may have to find a good second hand one if no one can recommend a good pattern one.
Someone in my BMW club just restored an A65 and he too was moaning about the excessive noise produced by his new pattern silencers.
An someone could perhaps recommend a decent silencer to the Harley folks. . . !
Hi,
Not specifically BSA, but there are noises being made in the EU and Germany re banning motorcycles from some Alpine roads due to the noise nuisance of some bikes - no mention of cars though.
Strange that Germany, that has quite strict 'Type Approval', have bikes that noisy. I must admit that there is nothing more annoying than hearing bikes yowling through the mountains for miles so non-motorcyclists must find it really offensive.
Dave.
I got mine from armorers and it seem fine, the pipe did not fit though, sent that back
mines a 1967 WD B40 push fit into the head, it leaks and causes popping in pipe when shutting off anyone got any idea how to seal it
Interesting to read about Armours.
I ended up buying a silencer from them. Very nicely made but the silencer body was not in the right place. The kickstart fouled it by about 1/2 inch. Got it to fit as there was enough down pipe to allow the silencer to pull back 1/2 inch. Had to make a new modified rear bracket though, but the sound is much better than the last one I had fitted.
Did check the Armours silencer against my old one and an original one and found the silencer body did start too close to the downpipe allowing the kickstart to foul. I have emailed Armour but am awaiting a reply.
I have a push fit exhaust on my M21 and I have been told the joint can be sealed using a small amount of black builders silicon compound. I have not done it yet, trying to tap in the pipe first with encouraging results although I suspect it will come loose again. This greatly reduces the noise.
You can use exhaust silicone to seal the joint. Garages don't use GumGum often nowadays. They use a high temp silicone to seal joints and also as a gasket for flanges. The only downside is that if you buy a big tube of it only to use a tiny bit, the rest of the tube will cure over 6 months or so wasting it.
If you have got a friendly local garage, ask them for a bit. Used to all be red in colour. Not sure if you can get black.