PT: Exhaust Quiet Exhaust?

Kevin Emery

Well Known and Active Forum User
VOC Member
Hello

I live in the UK. I am looking for a quiet exhaust for my C Series Rapide. Has the VOC spares company ever developed a quite exhaust? I am willing to give up HP, as my Rapide will still reach the legal limit even with a few horses removed.

Why? I think with the current trend for idiots to ride bikes with very loud exhausts it won't be long before the government reduces permissible sound levels on all vehicles. I live two miles from the A30 and on a sunny Sunday morning I can hear the bikes screaming through. Then there are the 'sound cameras' that are coming!

Could the Vincent Spares company be proactive here and develop a quieter exhaust that looks the same as the original before the government forces us to?

I would be your first customer.

Kevin
 
Last edited by a moderator:

vibrac

Well Known and Active Forum User
VOC Member
While it would be possible to reduce the Vincent exhaust sounds at a particular rev range with a side chamber under the bike (4.800 anyone?) any overall reduction of an order of magnitude would be impossible without a very large increase in silencer size and bulk you only have to look at the volume of a standard modern bike to see that.
Its quite simple, that Promenade Percy and his bypass mates(a great pre war name) all have non standard silencers sort that first
 

Dave Hulstone

Well Known and Active Forum User
VOC Member
The quietest silencer I’ve ever used on my 600cc Comet is the spiral baffle type from VOC spares. It is restrictive obviously but not by much, in my opinion.
 

vibrac

Well Known and Active Forum User
VOC Member
On a racer the noise limit for classic bikes is now 105 Db not many Vincent road silencers would pass that. I tried a new tack with my Grey Flash I built a silencer with a 2" straight through. The section in the silencer was perforated the difference was I made the body from alloy tube and the walls are 1/4" thick and I filled the gap between perforated pipe and wall with acoustic wadding, my thinking was thin walls transmit sound and vibrate. the result is very heavy but it passes the noise meter


1684323459117.png
 

Speedtwin

Well Known and Active Forum User
VOC Member
Comet 120 dB at 3/4 throttle on the H scale
Rapide 140 dB AT 3/4 throttle on the H scale
Shadow 145 dB at 3/4 throttle on the H scale

Although differing measured sound volumes they all have very different sounds most likely due to types of exhaust silencers.
The H scale:
My dog Harvey is an exhaust expert this is him below relaxing in his workshop.
Harvey can hear my friends or myself approaching the house from around a mile away.
He can differentiate between bikes by their sound.

He pre warns all inside the house of the imminent arrival of a bike.
His favorite long range detection machines are Harleys which he hears from around two miles away.
He doesn't rate them, nothing on the bark scale, I put this early detection down to a lower tone.

Harvey gets the Comet at around a mile away and the Rapide can sneak right up before the Harvey alarm goes off.
He is a huge fan of pre war singles,JAP engines especially which come in at two barks or three miles away.
All I need to do is teach him to put the kettle on when he hears me coming home.

I am a firm believer in not adding extra silencers to machines loud pipes do save lives.
Enjoy the weekend and the journey.UHPD3329.JPG
Al

The Vincents can get much closer before the Harvey alarm goes off.UHPD3329.JPG
 

Peter Holmes

Well Known and Active Forum User
VOC Member
Al, you have triggered my memory, when I was courting my first wife, the family had a Black Labrador cross, I cannot give you accurate distances, but that dog knew I would be arriving on a Vincent long before anyone else had an inkling, sometimes bounding up the road to greet me, and then bounding alongside me until I arrived at my destination, the dog by the way was far nicer than the part owner!
 

erik

Well Known and Active Forum User
VOC Member
To my mind it should be possible do ride the twin really quiet when you don`t open the throttle very much.And if your timing of the camshafts is a little bit wrong it can produce more noise than necessary.Erik
 

Alyson

Well Known and Active Forum User
VOC Member
In regards to Loud pipes save lives. I can admit I agree. I'm worried about these electric machines that no one can hear. Maybe a slight whirrring or even a hummm but for the most part, if you cross the road, there is no fore warning regarding eminent danger. A blind person needs to be wary now too. My 2 cents for the day and now my pockets are empty ;)
 

greg brillus

Well Known and Active Forum User
VOC Member
Well we all had noisey cars/bikes when we were younger, but the droning sound within a car quickly wears off, and becomes nothing but tiring on your ears and your brain........Loud pipes saves lives.......I dont think so, the noise is usually as the bike passes you and simply scares the crap out of you as they go past.......more obnoxious than anything, by riders drawing attention to themselves........Yes nice to have a good note, but only on a stock Vincent could you run an open pipe and not be anoying to yourself and others.......Once you up the comp and some bigger cams, the noise with open pipes is too much........tried all the above.......all good fun.
 
Top