Author Topic: excelsior two stroke exhausts  (Read 5109 times)

Offline safe history man

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excelsior two stroke exhausts
« on: August 17, 2015, 08:40:05 PM »
hi fellow bikers ,building a 1934 Excelsior as you know managed to put the rebuild engine in to find it had the wrong flywheel on got it started by subtracting TDC 90o and it fired up could it be the wrong flywheel ,also the silencers had a rattling baffle inside ,looked like an auger about 250mm long the exhaust looks very simlar to a fishtail velo silencer the engine is a Mk14a single villiers with a twin exhaust port ,my question is , are the auger type baffles correct and has anyone come accross them photos to follow
« Last Edit: August 17, 2015, 09:38:19 PM by safe history man »

Offline R

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Re: excelsior two stroke exhausts
« Reply #1 on: August 18, 2015, 12:25:17 AM »
I have a nos Norton muffler with auger baffles in it (not removeable though), so the auger part is a common type of baffle.
No idea if its correct for your Excelsior though. Being removeable suggests it was for 2 stroke use, so you are part way there.
 2 strokes back then weren't terribly scientific, so if it quietened it down was probably enough.
All you can do is try it and see how it goes.

Offline 33d6

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Re: excelsior two stroke exhausts
« Reply #2 on: August 18, 2015, 01:05:43 AM »
To add to R's remarks you should appreciate that it is not a Villiers exhaust but the Excelsior factories own. Villiers catalogued their own exhaust systems at the time. They were the very beginnings of the expansion chamber as we know it and neither elegant nor fashionable so very few used them. The Brooklands style can as used by Excelsior was fashionable and sold bikes but did nothing for two-strokes.

Originally your silencers would have coked up pretty quickly and the carbon would have quietened things down a bit. They won't coke up with modern two=stroke oils so won't quieten with use. Your removable auger would have been cleaned out by the owner occasionally but probably not the body of the silencer.

There would be very few 1934 Excelsior left with the original exhaust fitted and even fewer of the original owners left to ask. As R says, all you can do is try it and see how it goes.

Offline safe history man

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Re: excelsior two stroke exhausts
« Reply #3 on: August 18, 2015, 05:28:24 PM »
we started the bike for the first time last weekend and what a racket so will come up with some way of decreasing the Db,when i cleaned the silencers out it also was stuffed with chicken wire its nice to know that the exhausts  are original and i have found a repro sales catalogue and the bike has the silencers on ,one other problem was we could not get the bike to fire at first ,when we checked the flywheel and looked where the cam was to co-inside with the points it was out ,we set the points set the engine to TDC ,backed it off 1/4" and checked the flywheel and we needed to set it back anti-clockwise 90o tried the bike and it fired ! could it be that someone has replaced the flywheel from another model ? or have i missed something ,anyway its running
got all the chrome off to be plated sort the baffles out when we get them back getting there slowly but surely 

Offline 33d6

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Re: excelsior two stroke exhausts
« Reply #4 on: August 19, 2015, 01:59:52 AM »
Congratulations. That's very nice. I would make some suggestions though.
First, by the time the Excelsior was produced Villiers were numbering their flywheel magnetos. Both the flywheel and backplate shared the same number so it's easy to see if yours are a pair.  We can talk further about it if something is odd. We can also talk about the ignition advance and retard.
Secondly, I suggest you slightly re-route the oil feed pipe from the tank to engine. It's basically a gravity feed once the oil goes through the sight glass, there is no pressure to speak of.  Not that there is much pressure in the Villiers system anyway. It has to be downhill all the way from the sight feed to the engine.
Thirdly, to quieten exhausts I find rolls of stainless steel wool as used for wood finishing far more convenient than chicken wire. Even stainless steel kitchen scouring pads can be useful. 
Otherwise, what a sweetie.
Cheers,

Offline murdo

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Re: excelsior two stroke exhausts
« Reply #5 on: August 23, 2015, 10:49:02 PM »
Will be a nice little bike when finished.
My Royal Enfield model A (two stroke) has the auger baffle in the original muffler.