Noisy Exhaust

peter.clews

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Know thy Beast on Page126 seems to exactly sum up my view Quote.. "internal spiral baffles seem to suit better than the straight through absortion type whose crisp staccato note soon becomes offensive to the public and tiring for the rider." I rode it today after a 3 year lay off .The grin is back on my face Peter:)
 

harvey

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Silencer

The original Vin silencer sounds good but to me seems a little noisy. It may be a bit on the small side to give good silencing and also low backpressure. Modern bikes have tailpipe inserts available in Demon Tweeks etc. and this idea could be used. The insert fitting dia is
too big (2") to fit the Vin tailpipe so a modification to the insert fitting dia is needed. Rest of the insert is 33mm I believe. Or make your own.
If the absorption silencers mentioned are the same size as the Vin silencer then they may not be too effective, but Demon Tweeks have various absorption types including a repackable one which is 4" dia which should be able to fit in place . This one is repackable, dismantleable, can be cut to length(!), and can take an extra silencing insert. It is however black in colour. Don't know if the overhang on the Vin system would be a problem for the 2-piece construction. Weld it up? It fits a 1-3/4"pipe so a packer is needed?
A bracket to fit the Vin would need welded to the silencer.
Demon Tweeks also have a variety of S/S units but mostly seem to be for larger pipe sizes. They do the Supertrapp mentioned by someone.
This is all from the Car catalogue .......
 

Prosper Keating

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Know thy Beast on Page126 seems to exactly sum up my view Quote.. "internal spiral baffles seem to suit better than the straight through absortion type whose crisp staccato note soon becomes offensive to the public and tiring for the rider." I rode it today after a 3 year lay off .The grin is back on my face Peter:)

Me too! I put the Burgess-type pot back on for a working trip to the middle of France and saw 50 mph-plus in second on the Comet's clock accelerating away from a roundabout. I thought I was in third...

Mind you, going into town this morning at 0630 hrs to fetch some croissants etc, I did feel a bit guilty about the racket as I passed through sleepy villages, especially when I had to throttle down for speed humps. The noise is pretty brutal. On the open road, I tend to use earplugs as a matter of course, so I don't notice it but the VOCSC pot is definitely going back on when I get back to my normal urban environment!

Still, the grin factor is certainly there as you hunch down on a long straight back road through the local forest with the needle of the Smiths just past 90 mph. Bursting out from the trees, the sight of cattle a quarter of a mile ahead getting to their feet and running away does however elicit killjoy pangs of remorse...

PK
 

Howard

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Just a short anecdote for those who haven't tried this.

In the 70s I took my Egli on the track (Silverstone) for the first time at a VMCC practice day, complete with roadgoing indicators etc and was having a great time playing racer. A friend I was with (Richard Kettle) was there with his racing shadow, he threw me a piece of rusty exhaust pipe, and told me to replace the Vincent type (don't know if it was spiral or what) silencer with it. I didn't like the rusty bit of metal, but it made the bike sound like a real racer, so I went out for another spin. I rode down the feed-on road, looked for a space in the traffic and wacked the throttle open. The difference was so great I lost my grip on the handlebars with the improved acceleration.
All this extra power without even tuning the carbs to suit, showed me just how critical the silencer is, hence I use the Dunstall can and earplugs. So far "It's standard fitment on 1974 Egli Vincents Officer" has placated the boys in blue.
Try a piece of pipe reaching back to the rear wheel spindle (tuned for about 4000 rpm), when someone finds a high tech quiet silencer that gives the same performance I think we'll all have one.
 

Howard

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Still, the grin factor is certainly there as you hunch down on a long straight back road through the local forest with the needle of the Smiths just past 90 mph. Bursting out from the trees, the sight of cattle a quarter of a mile ahead getting to their feet and running away does however elicit killjoy pangs of remorse...

PK[/QUOTE]

Just read your last paragraph. I'm sitting in a miserable office, looking out at a brick wall, watching the rain, reading about you riding a Vincent to fetch croisants in a beautiful part of France, and you're feeling sorry for the cows!!!!!!!!!!!!!!!!!
 

Bazlerker

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I regard a slightly loud muffler as a safety factor...car drivers are more likely to hear me through their cel phone conversations than not..2 blips of the throttle is more satisfying, and more likely to be heard, than an altette horn.
 

Prosper Keating

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Looking at some of the locals around here, Howard, it's not just the cows I feel sorry for but the sheep as well. If it makes you feel better, it's clouded over and I just got battered by hailstones. And a bird dropped one on my head.

Now, a technical question, since you mention carb tuning: Standard compression ratio, magneto a couple of degrees retarded from book figures to allow for unleaded. Small Koni filter for reasons of space, NGK 8ES plug with electrodes cut away for clean starting and running, again with occasionally dodgy fuel.

289 Amal, needle 2nd position from top, giving good, crisp acceleration up to 50 mph in 2nd if I cane it. However, the 90 mph-plus was downhill whereas I have seen it on the level. So here's the rub: 200 main jet. Should I drop to 190 or 180 to squeeze those last horses out on full bore?
 

Howard

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Looking at some of the locals around here, Howard, it's not just the cows I feel sorry for but the sheep as well. If it makes you feel better, it's clouded over and I just got battered by hailstones. And a bird dropped one on my head.

Now, a technical question, since you mention carb tuning: Standard compression ratio, magneto a couple of degrees retarded from book figures to allow for unleaded. Small Koni filter for reasons of space, NGK 8ES plug with electrodes cut away for clean starting and running, again with occasionally dodgy fuel.

289 Amal, needle 2nd position from top, giving good, crisp acceleration up to 50 mph in 2nd if I cane it. However, the 90 mph-plus was downhill whereas I have seen it on the level. So here's the rub: 200 main jet. Should I drop to 190 or 180 to squeeze those last horses out on full bore?

My opinion, keep to the 200 jet. You sound as though you do a lot of your miles on the main jet, and I think it's better to run rich, safe and a couple of BHP down (on the road). You could do a plug chop, but as you say there's always a chance of dodgy fuel.

Have you tried lead additive with octane booster and put the timing back to standard? I'm hoping to get my Egli back on the road next month, and it's always run on leaded or LRP previously, I've got a bottle of "stuff" but I don't know what the outcome will be.

Howard

ps thanks for trying to make me feel better, but I think our weather's still worse and the birds are bigger too.
 

Bazlerker

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Run the larger jet..and don't spend a lot of time trying to wring those extra few mph out of the beast..or be prepared to rebuild the engine every few years..
Phil Mahood gave me some very sage advice a number of years ago..."The manual says it will cruise at 80 mph - it will, but not forever..cruise at 65 and it will do so for a very very long time"
I open my beast up every time I take it out, once properly warmed up..I never let a Harley pass me ( though thats getting harder and harder - they are getting fast!)..but I cruise at 65mph...
 

Mark Fisher

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I have to agree with some of the other guys about jetting and silencers. With thanks to Glenn Bewley in tennessee here's what i learned:
After a total rebuild my bike (52 shadow) was really slow, although it would run very smoothly and quietly (spiral baffle silencer), I suspected that I had got the valve timing wrong when I fitted the new cams (megacycle mk2) as the carbs were brand new and I run a BTH. I was having severe gear selection problems also, I'm not too proud to ask for help so I took the bike over to Glenn. He fixed the gearbox so it now works perfectly and initially even he could not get the bike to perform like it should. After some research he figured out that the problem was my cams. Basically they are smilar to lightning cams that are designed to run with straight through pipes, so he put an old burgess silencer (no baffles) on the bike and found an instant improvement. After experimentation he ended up settling on 200 main jets (sound familiar?).....Result: the bike is totally transformed, it pulls like a train, I got over a hundred on my first test ride when I went to pick it up, one happy camper! It is a bit noisier now but not as bad as the average harley.
 
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