Author Topic: Coventry Eagle  (Read 4573 times)

Offline 33d6

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Re: Coventry Eagle
« Reply #15 on: May 24, 2019, 03:50:59 AM »
The flywheel magneto being minus lighting coils is typical of early 1930's motorcycle electric lighting. The Villiers system only produced alternating current and could not be used for charging a battery as it was. The technology to do this was not yet available to the motorcycle world. To get around this so as to provide a steady beam of light rather than the Villiers flicker several manufacturers(including Coventry Eagle) fitted a 6V dc dynamo driven off the engine shaft by an extra sprocket. This gave means to charge a battery. Very easy to do as it was all standard bicycle sprockets and chain.
The type of dynamo then available was equally primitive as the current produced was unregulated and fluctuated all over the place blowing globes and boiling the battery.  This was "controlled" (note quotation marks) by the rider with a half charge resistance fitted in the headlight switch. One glance at the headlight switch will reveal whether you have an original switch fitted, Rex.The half charge resistance is very obvious.

All of the above is high drama if you want to explore the excitement of early 30's lighting but the advent of modern electronics means the original Villiers system can be updated very easily and is by far the easiest way to go. Be aware that Villiers flywheel magnetos were made in paired sets so the brass flywheel and the backing plate share the same lengthy unique number. Just finding another back plate already fitted with lighting coils and using it in conjunction with the flywheel you have is not as simple as it looks.
 
Welcome to the Wunnerful World of Williers.

Online Rex

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Re: Coventry Eagle
« Reply #16 on: May 24, 2019, 09:45:24 PM »

All of the above is high drama if you want to explore the excitement of early 30's lighting but the advent of modern electronics means the original Villiers system can be updated very easily and is by far the easiest way to go.

I'm intrigued. Is there a link to any info on this?
The Coventry Eagle has the frame number 14210, engine number GYF 9828, and spare engine number KZB 595. Any information to be had from that?

Offline 33d6

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Re: Coventry Eagle
« Reply #17 on: May 26, 2019, 03:19:27 AM »
Hi Rex,
I don't know of any links relating to 1930's electrical systems. They don't excite many people. It's back to old fashioned books. About the best I know that gives a broad overview of everything available back then and how it operated is "Modern Motor Cycles" written by Arthur W Judge and published in 3 Volumes by The Caxton Publishing Company, Limited. Clun House, Surrey Street, London, W.C.2  somewhere around 1933. It predates all the modern identification rules used today so I can't be precise about the publication year. Volume II goes into some 120 pages of detail about British electrical systems of the day and covers all makes. I've never found anything better.

"Modern Motor Cycles" is not easy to find and not cheap when you do. I would suggest going to your local proper library and talk to a trained librarian (not a volunteer). They should be able to locate a library holding a set. I'd be amazed if you were allowed to borrow them so plan on an extended library visit to have a good read. If you're a sweet talker they may do an inter library loan so you can read them at your local library without too much travelling.

As far as the wee beast is concerned I'm well pleased to tell you it has a place of honour in the VMCC Register of Machines. Its Register number is 10685 and both frame, engine and reg numbers are as you quote.   I have the 1st and 3rd editions of the Register and although it isn't in the 1st edition published 1969 it is in the 3rd edition published 1992 so it has been around in its present form for at least 30 odd years.

Its nice to know this info confirms my earlier advice that the engine is a composite Super Sports top end on a Mk 12C bottom end. Effortless to do with all standard Villiers parts just by re arranging how you assemble them.

The spare engine with the prefix KZB is a 196cc Super Sport made 1929-40 and usually used as a replacement for the 175cc Super Sport. Absolutely no difference in performance from the earlier 175.  I have no idea what the extra 'B' at the end of the prefix KZ refers to. Villiers would make minor alterations to their engines to suit various makers and identify them accordingly but many of these identifications have been lost over time. These minor alterations never affected engine operation or repair in any way so are never much concern. The classic example was in 1933 when Douglas mounted a 150cc Mk12C Villiers horizontally in their Douglas Bantam. As the engine was now horizontal the crankcase drain had to be re positioned to suit, otherwise it was halfway up the crankcase. These engines have an extra 'H' after the standard engine number GY prefix so are numbered GYH****. It was nothing that affected the operation of the engine nor its maintenance.   As you can imagine these little nonsenses get forgotten over time. Your KZB seems to be one of them.

Do keep us informed. You have the makings of a little ripper of a bike that is much under rated. Just learn to wring its neck. Take no prisoners!

Online Rex

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Re: Coventry Eagle
« Reply #18 on: May 26, 2019, 09:19:18 AM »
Thanks for the detailed reply mate. After a lifetime working with Amps and Volts the original Villiers lighting set-up holds no fear, but I'm interested in the modern electronic upgrades you alluded to.
Getting the lights working isn't really a priority, but if I get hold of a lighting coil I'll wire it all in, but if they're difficult to obtain then LED globes front and rear fed of a Cyclon battery (hidden in the toolbox or whatever) would be more than adequate.
First job is to sort the dragging clutch. The last bloke had a reline by Villiers Services but clearly it now needs setting up better as it drags enough to stall the engine and there's a ton of slack in the cable/lever too.
According to info found on the Net, it started life as either a G24 150cc or a G25 200cc. Shame that some sod sold off the original 2-letter four-number reg number though.

Offline iansoady

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Re: Coventry Eagle
« Reply #19 on: May 26, 2019, 09:45:51 AM »
I'd have thought that getting rid of the ton of slack should go a long way to reducing the clutch drag.

I look forward to many stories of trials and tribulations....
Ian
1952 Norton ES2
2008 Yamaha X-Max 250

Offline 33d6

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Re: Coventry Eagle
« Reply #20 on: May 26, 2019, 10:49:52 AM »
Most of your dragging clutch issues arise from accumulated wear in in every component between the handlebar lever and the clutch. All it takes is a little wear in the clutch lever pivot, the lever pivot on the gearbox plus the 1/4" round it pivots on and so forth through the whole mechanism for all the clutch lever movement to be taken up before it lifts the clutch. You can also bet the adjuster screw in the gear box lever is half worn away making it fussy to align properly.   
The clutch pushrod is also noted for boring a recess in the clutch plate which also upsets things. None of it is dramatic wear. Just minor wear in everything that can wear. Its the accumulation that causes the problem.
Later Albion clutches have a mushroom head on the short piece of pushrod that bears against the clutch so you can eliminate that wear point. Nowadays I make all new including a new pushrod and re bush every pivot to get optimum performance at all points. Luckily Albion boxes are idiot simple and so easy to work with. Makers used Albion because they were cheap and unfortunately when you shave costs to the bone to make things cheap it doesn't leave generous allowances for wear.   Then again, sort it now and you will never have to do it again in your lifetime.

Finally, modern electrical upgrades. Essentially the original set up was so basic that a modern upgrade merely means a modern solid state rectifier so the battery can get a full charge plus a modern zener diode arrangement to ensure a happy battery plus LED lights. Nothing super dooper and exotic. Merely bringing the electrics up to what is regarded as everyday stuff now but exotic space age stuff when viewed from a 1931 perspective.

Online Rex

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Re: Coventry Eagle
« Reply #21 on: May 26, 2019, 05:14:11 PM »
I look forward to many stories of trials and tribulations....

I don't quite know how to take that Ian.. ;)

Offline iansoady

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Re: Coventry Eagle
« Reply #22 on: May 27, 2019, 09:57:16 AM »
In the spirit was made of course.....
Ian
1952 Norton ES2
2008 Yamaha X-Max 250

Offline john.k

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Re: Coventry Eagle
« Reply #23 on: May 27, 2019, 01:29:26 PM »
Villiers seem to have invented the flywheel magneto around 1920........think of how many have been made in the century since ..........even now the solid state ignition on little engines is still a flywheel magneto,just has no mechanical parts...I have an antique pump with a Mk 10 /100cc 4 stroke on it,the spark was so weak it couldnt be seen in daylight,yet the little motor starts and runs reliably,and has been used industrially in the years since.Bit smoky tho.