poor quality repop silencers

Jim Richardson

Well Known and Active Forum User
VOC Member
I noticed at the weekend, that on a local test run, the Rapide hit 80 easy in 3rd, but would only increase slowly in top.
It may be worth swapping the various silencers around to see if there is any difference.
 

Black Flash

Well Known and Active Forum User
VOC Member
I had a Campbell one on a Comet with lowish compression but MKII cam.
The Comet hammered the baffles out on a single 90 miles run with the exhaust note getting "crispier" and speed going up with every mile.
At the end the speed was great but I got send away from the MOT station due to excessive noise and had to scrap it.

Bernd
 

Oldhaven

Well Known and Active Forum User
VOC Member
TOGA
I'll be using a never used Toga straight through muffler on the Rapide when spring gets here. What is the verdict on that one? I can see that it has perforated baffles around the large part of the can, but what is behind them and does it last? the chrome looks great.

Ron
 

Howard

Well Known and Active Forum User
VOC Member
I think we're in danger of tunnel vision here. The silencer won't suddenly give 6 bhp more than standard, we're not going to boost a standard Rap to 51 bhp. I suspect the new VOCSC silencer will give more or less the claimed 45 bhp, and less well designed silencers will give less power. Don't forget, the power probably comes from less back pressure, that will make it necessary to rejet the carbs to take advantage, and to make sure you don't run too weak.

Jim, I think you're reaching the limit of good acceleration at 80 mph on a Rap if you change up there. Not only is the acceleration starting to tail off, but you drop the engine speed which reduces the power available, if I want good acceleration I stay in third till well into three figures.

http://www.vincent-hrd.co.uk/story.html

H
 

nkt267

Well Known and Active Forum User
VOC Member
It's a shame you are so far away, But I am very pleased with my Stainless one from Armours,
I've had one on the Comet for quite a while and am very pleased with it..Same performance as the Toga I had but a little quieter,You could easily hear the Comet(mk2 cams) from over 1/2 mile away:D,,John
 

usefulidiot

Well Known and Active Forum User
Non-VOC Member
I am not expecting an increase over stock, i just would like it to run as well as possible and to cruise in 4th at 75 without lugging the engine. I'm guessing that I'll have to move up to at least 180 mains possibly 200's here at sea level if my muffler is currently as restrictive as its reputation. I'm thinking with stock performance restored and possibly 2 teeth up in the back to bring the revs up at my happy cruising speed...I'll get the desired effect. That article was very informative. I knew 3rd and 4th were widely spaced but wow they are very widely spaced.


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usefulidiot

Well Known and Active Forum User
Non-VOC Member
Then I hope the silencer changes it because it doesn't like to accelerate in top gear at that speed....downshifting to third is the only way to get it to go anywhere currently


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Albervin

Well Known and Active Forum User
VOC Member
When I did the rebuild on my engine last year I bought a new silencer from an Australian supplier because I had not been happy with the current one. When the bike was finished I put the old silencer on for test rides. It was suddenly a lot crisper and I felt I had better throttle response at moderate to higher revs. I discussed this with my friend who assisted in the build and he thought we had timed the cams a lot closer to optimum compared to the way the bike was before the rebuild. I still haven't fitted the new silencer. Oh, another thing, the bike has always run a bit rich but after the rebuild it is noticeably less so to the extent I need full choke on both carbs to start from cold instead of half choke. I have always had a 48T rear sprocket due to the hilly terrain and find the bike will still happily cruise at about 70 mph but 2nd and 3rd gears are much more useful when attacking hills; 1st is only for moving off and hairpins.
What size concentrics are you using?
 
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