Waratah speedo

[R]

So I've come across a neat little Smiths speedo, 2 & 1/2 inch, and pondered fitting it to a Waratah 1945/6 125cc.

I don't think speedos were even an option then ?, so this has me pondering.
How to organise a speedo drive.
And, laughing, is 40 mph going to be enough !

Thoughts ?
Indian Bullets and plenty o jappas have a speedo drive off the front wheel.
Where will the ratios be.

Possibly off an autocycle ?

[R]

P.S. This Waratah is for all intents and purposes identical to an Excelsior Universal, mit girder front fork.
(the tank decals are different !)(and is black not maroon).

https://www.thenostalgiashop.co.uk/cdn/shop/products/DSC2637.jpg?v=1652465153

[R]

And this 1950 model shows a speedo.

So where was it driven from - the rear wheel ?
Cable just disappears in the pic.
Plunger frame tele fork model
https://i.postimg.cc/Dw73dhFH/Excelsior-Tom-Byrne-Aug-1950.jpg

[Rex]

I don't recall ever seeing a post-war Villiers-powered lightweight with a front wheel-driven speedo, but then as I also don't recall ever seeing a Villiers unit with a gearbox speedo connection, then it must have been from the rear wheel.
Maybe a Bantam (or similar) speedo drive would do the job?

[R]

Should have mentioned that the rear wheel has a sprocket one side, and the brake on t'other.
This will make it difficult. ?

Not familiar with a bantam drive.
Hmmm, looks like the same 2:1 Smiths as for the bigger bangers.
https://www.bsabantamclub.com/wp-content/sp-resources/forum-image-uploads/rogereld/2020/06/IMG_4941.jpg

Might investigate if it can be squeezed into the front (girder) forks.
Or one of the Indian ones.

[cardan]

This is how Acme did it, c1948, with a D speedo (like a Bantam) and external drive from the front wheel.

Looking at most just-post-war Waratahs, Acmes and so on I'd say few had a speedo when new.

Is the Waratah like the one in the Powerhouse museum, with the gear lever through the tank?

Cheers

Leon

[33d6]

Your speedo head should either be a Smiths ‘D’ shape thing as used on the Bantam and other lightweights or the once common 80mph Smiths as used on WD M20’s and the like.
I’m going through the same nonsense with my 1940 Excelsior Universal. Your immediate post war bike shares the same front fork as my immediate pre war bike. In fact the whole front end forks, wheel, brake, etc, are identical. Luckily I found a complete N.O.S front wheel speedo drive setup for the James M.L which again shares the same front end. It only varies in the means of holding the right angle speedo drive in place.. A bent bit of tin to the front axle on the ML or a straight bit of tin to the fork leg on the Excelsior. Either way the kit just bolts straight on.
I have everything but tucked away. If you wish I’ll haul it out and put up photos for you, plus count the number of teeth on the drive gears.

[R]

Thanks for the replies - helpful already.

My bike is identical to the one in MAAS
Almost identical.
My tank has very fine twin gold pinstripes.
The MAAS has one very wide gold stripe.
I wondered if that happened in the resto ?

A photo of the components would be marvellous - at your leisure.
Been pondering this for years.
Don't think I've ever seen a speedo fitted to just postwar bikes.

Note that a speedo was listed as an option for the 125cc versions, even a few years later.
There are brackets on the girder fork to bolt it to on mine though.
https://i.postimg.cc/Dw73dhFH/Excelsior-Tom-Byrne-Aug-1950.jpg

P.S. I wondered how a bike without a speedo could be legal, even then ??

[cardan]

Presumably the right-angle speedo drives are (mostly?) the same as these. (I dropped a box of speedo bits from a high shelf retrieving them, so be grateful...) They have aluminium bodies. I think the same unit is used for external gears, or for gears mounted inside the brake drum.

Of course the ratios are a nightmare. One of these I measured to about 3:2 reduction (three turns of the input gives two turns of the output). Then there are the driving gears from the wheel to the box, then the calibration of the speedo. Are you sure you don't want to just use a little Garmin bicycle GPS unit - no fitting at all required, perfectly accurate, can be swapped from bike to bike, and will record a map of there you've been and how fast you went there!

Leon

[Rex]

Very effective, but so incongruous on old bikes.

[33d6]

For some mysterious reason I can happily sign in on my IPad but not my PC which has all my photos. When I resolve this mystery I shall put up the speedo drive shots I promised. I even have one showing Excelsior’s own way of mounting the right angle drive.
There are times when I could do nasty things to electronic devices.

[R]

Look forward to it.

And be thankful we didn't get a super-magnetic storm ?
Which has the potential to wipe out all electronic devices !
Ala the Carrington Event of Sept 1859.

While we contemplate that, I have found I have a right angle drive and cogged drive wheel.
On a military project.  The mounting system will be of interest, as will the tooth count.
Cheers.

[33d6]

I can give you the tooth count without photos.
The speedo drive kit consists of a selection of two large drive wheels, one of 50 teeth and t’other of 48 teeth plus the needed attachment devices and rt/angle drive shaft. The larger is of a lightweight material (aluminium?) anodised black, dished to suit a spoked wheel and has an ancient label annotated “James”. The smaller wheel is bronze and flat without dishing but has the fancy attachment doovers needed to spread the load across several spokes. These fit either drive wheel.
The small driven wheel on the rt angle drive shaft has 17 teeth. It is riveted in place and thus a permanent fitting .
The tooth size is 10DP.
The PC continues to defeat me.

[R]

Can you directly load these pics to somewhere like postimage ?

You don't need to sign in, or need to pay, or anything.
Just 'choose images', locate in on yer puter, click to upload, and voila.
Copy-n-paste and save the directlink in the 2nd row
And also save the final 'delete' link, in case you wish to later erase them.
Further instructions on request, but even I find this bulletproof.

https://postimages.org/

[john.k]

The Smiths rt angle drives are pretty common as they were also fitted to a lot of diesel engines as tacho drives .............although they were quite expensive ,as I recall ,around $100 in 1970.