Arthur Conan Doyle's (Sherlock Holmes) motorcycle

[Cooljerk]

A relative of mine was a friend of the Doyle family and was given a photograph of Sir Arthur Conan Doyle sitting on one of his motorcycles. He was a real motorcycle enthusiast and also raced. I was wondering if someone can identify Sir Arthur's motorcycle.
Here's an article I posted about it several years ago including the picture. I still haven't gotten a clear answer about the identity of the bike.
http://jimmy-williams.hubpages.com/hub/Arthur-Conan-Doyle

Jimmy Williams, aka Cooljerk

[pete at occhiolungo]

I think that is a ROC.  They were made from 1904 to 1914, and Arthur Conan Doyle was an investor in the company.  Eventually they produced the Wall Auto Wheel, which is a bit better known than the ROC bikes.

regards,
Pete

[Cooljerk]

Thanks for the interesting input. I would love to see a  sample of a ROC like ACD's. The only ones I have been able to find do not have a flywheel on the right side of the engine.

[R]

That SV24 registration should be traceable - the records may even still exist, depending on where it was issued. (Surrey ?)
This has to be at least a few years into the 20th Century.

[Should have read all the comments first, shouldn't I.
Has been traced = 1905 ROC...]
Elsewhere it notes that 1905 Roc had external flywheels both sides of the engine.

That monumental high-rise mounting for the numberplate has to be noted !!

[pete at occhiolungo]

ahh, I didn't even see that there were comments on that page.  I guess they solved it 9 months ago...    A local friend has a similar ROC with long frame and curving top frame tube.  Not many of them exist anymore, but the ROC rear hubs were used by several different manufacturers.

[wetdog]

i had a roc hub in a aldays matchless i had @1912 live axel . good hub well made . the bikes still about

[cardan]

I assume the motor with a flywheel on each side is a Kelecom unit (sometimes also branded V. Antione et fils or VAF): unusual because the cylinder screwed into the crank case and was locked in place with a pinch bolt. If you zoom in the the picture you'll note there are no studs and nuts to hold the cylinder on. I have a reference to ROC using an 85 x 85 version of the Antoine motor in 1905.

I've seen the single-outside-flywheel version of this motor out here in Australia, but I've never seen the two-flywheel one.

Leon

I should add that in the UK Ormonde were probably the largest user of this type of motor, but not, I think, the two outside flywheel version.

[wetdog]

very interesting machine , do you think this might be a sleeve valve enging ? the front number plate arangment is illustrated in a book i have 1911 but may have been used earlyer i know , the rear hub belt wheel looks like one ive seen fitted to triumphs and villiers (with the large spokes ) do you think this bike is a single speed ?

[R]

Sleeve valves and gears-in-rear-hub would both be unlikely in 1905, they were still in the future ??

Although there were some sharp minds on the job, thinking about how such things could be achieved.
It was said that Alfred Scott and someone else in the same street in the same town both applied for an early patent for rotary engine designs, in the same year.  Smart street ?

[cardan]

No, not sleeve valve - just a mechanically-operated exhaust valve at the side of the cylinder, and an atmospheric inlet valve (just sucks open when the piston descends) above it.

The device in the rear hub is either a clutch hub or a two-speed gear. There was a "new" ROC two speed hub shown in 1907, which was said to much lighter and neater than the old one, so perhaps a 2-speed ROC was available in 1905. Bicycles had various 2-speed devices - mostly based on epicyclic gear trains - from the late 1890s so a 2-speed gear on a motorcycle would be unusual, but not impossible. I'm pretty sure that the NSU 2-speed gear in the front pulley was available in 1905. As r points out, some pretty good minds at work!

Cheers

Leon