What Frame is this?

[Denisj]

I am coming up at a loss on this frame… it is the oil cap that is unique to me. (Rookie Scott owner)
I am trying to sort this bitsa bike

The fuel tank seems incorrect/too tall
The oil filler cap is centered on the backbone right where all the veteran machines have the lifting hole (as I call it)
The radiator is a 4 point mounting… if that matters
The engine is 1915 and the wheels are “clincher” type with a rubber damper rear sprocket (maybe another bike)

Does this look familiar?
Where should I be able to find the engine numbers? There is nothing on the left side of the oil filler

Thank you!!

[David J Waring]

Very interesting ! I assume you mean frame, not engine number.
From my ownership of a 1913 machine, you need to look at the front of the headstock for the frame number, low down, about one inch up from the bottom bearing.
You may be looking for 4 digits, which face forwards, in a horizontal pattern thus :- X XXX, where the first digit is the factory number of the frame builder who made the frame and the other three digits are the actual frame number. With these three digits, it is easy to date the frame, according to the late John Underhill (past SOC Machine Registrar), who must take the credit for most of this information; if you find them, let me know.
Regarding the radiator, up to early 1915 the radiator was 4 bolt mounted, but with SQUARE honeycomb, not like yours, so the 4 bolt mounting on yours could be irrelevant, especially as the core does not have an inlet pipe – hence the two non-standard inlets into the header tank.
Does your frame have lugs for 4 bolts?
After early 1915, the radiator was 3 bolt, with a frame to match.
Regarding the oil filler, the 1912 Scott sales catalogue picture was the last year showing an oil filler behind the handlebars; in 1913, the oil filler was under the “nose” of the saddle.
Incidentally, thank you for your comprehensive profile – I really don’t like dealing with informationless nom de plumes!

[Denisj]

…No numbers!

I see the filler caps in the early machines, but I have not seen the small speedway type. Maybe this is a speedway frame? It is definitely a Bitsa bike. The Front brake looks like a ’22 and later piece and the rear wheel seems to be for some of the earlier machines with a brake on the right side and sprocket on left.
I see pictures of the parts in the books I have been reading in the past weeks.
– The radiator as you say is later model yet with dual upper tank flanges
– The engine is 1914-15
– Bosch magneto
– Amal brass carburetor
– Dual exhaust pipes on either side AND an outlet in the center for exhaust on the engine barrel
– Seat springs mounted on cross-bar welded to frame like the later motorcycles without oil in frame
– fuel tank? Maybe ’15 but does not fit the frame (too tall)
– Small oil filler cap in place of sidecar lug – aprox 1″ in diameter
– Scott front forks with guides (as far as I can tell)
– Front fender is in between the early thin type and I think 22 and later valanced type. It has provisions for the fork
– Front fork has lug for front brake arm

Are there any distinguishing features I should be looking for on this frame?

I acquired this bike with a heavily modified ’30 Rep and found through the seller these bikes were raced by the previous, previous owner. I assum this bike has been built up from war time pieces or maybe was new only to have all of its bits swapped for the more favorable (in owners opinion) parts for racing.
It looks like the project stalled when the 3 speed transmission was installed.

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