Author Topic: Hi Guys.. FACTORY RACER..  (Read 6009 times)

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Offline hazeltons

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Hi Guys.. FACTORY RACER..
« on: 29 Nov 2014 at 07:33 »
Hi All... I have purchased an F31 RACING machine in Europe & I think it is a genuine FACTORY RACER.. All comments I will appreciate.. It has correct numbers, but very different from standard models..Frame FD 111, Engine  ET103 Has "Hi tensile" Racing mag, Race TT Amac Carbs, UNIQUE RACING timing chest/Airbox, FACTORY Racing 3 blade forks, Slightly different indent cases, with MASSIVE oil pump.. etc;  Shows some street modifications for Tax & rego .. It was originally found from a deceased estate, sold by Bonhams & recently refurbished & purchased through Yesterdays.   I have owned many OHV Douglas machines over the years ranging from Sports '23 500cc, 28 DT's & SW5's.. I would like to hear from others regarding this wonderful machine & it's history, Regards Steve       

http://www.yesterdays.nl/douglas-1931-500cc-p-2952.html
« Last Edit: 29 Nov 2014 at 08:01 by hazeltons »

Offline cardan

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Re: Hi Guys.. FACTORY RACER..
« Reply #1 on: 30 Nov 2014 at 09:40 »
Hi Steve,

The photo attached comes from the Motor Cycle, 11 June 1931 and shows one of the 1931 Works bikes - a Junior mount but the Seniors were probably identical other than bore.

Its lineage seems to be TT/DT and it doesn't seem to have much in common with the F31. The 1932 Works bikes had quite a few innovations http://www.douglasmotorcycles.net/index.php?topic=5444.0

Cheers

Leon

Offline Doug

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Re: Hi Guys.. FACTORY RACER..
« Reply #2 on: 30 Nov 2014 at 21:55 »
Steve,

Sorry no, it not a factory racer. It is a F31 model based bitza, as confirmed by the frame and engine prefix, done up in a racing theme. Looks like it still has the F/G31 transmission, with the kick starter mechanism. Which is good, as those gearboxes are unique to the F/G31 models and hard to come by. Someone has installed a what at first looks like an early tall DT model airbox. If so, part of the bottom corners have been cut away, or this is a fabricated airbox based on the tall DT 'box. The DT airbox will have cut-off the internal oil gallery from the sump to the F/G31 airbox, so the constructor must have made other arrangements for picking up the oil.

-Doug

Offline Ian

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Re: Hi Guys.. FACTORY RACER..
« Reply #3 on: 01 Dec 2014 at 00:23 »
Whatever it is - its hot !!

Offline cardan

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Re: Hi Guys.. FACTORY RACER..
« Reply #4 on: 01 Dec 2014 at 05:54 »

Hot maybe, but the geometry of the kick start lever worries me!

Leon

Offline Doug

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Re: Hi Guys.. FACTORY RACER..
« Reply #5 on: 01 Dec 2014 at 13:43 »
Leon,

Douglas always had a problem when it came to providing a kick starter on the OHV models. Once they placed the transmission up under the seat, they backed themselves into a corner. Early machines like the OB and OC they mounted the lever on the engine and tried starting through the timing gears. But it was just not built robust enough. On the SW5 (derivative of the Dirt Track model), they just gave up and did not provide one. You bump started just like a racing model. Next were the F/G31 models and they decided that a road model really ought to have a kick starter. So they came up with the curious arrangement of carrying a counter shaft across the rear of the gearbox case. The counter shaft ran in bronze bushes and ran all the time, but only was loaded while you were kick starting the bike. This was a make-do approach to apply a kick start to what was in essence the three-speed (cross-over) gearbox as used on the SW5. The subsequent (and last prewar) OHV model, the OW/OW1, they adapted the four-speed gearbox from the then current side valve models. These had a 'conventional' kick start pinion and quadrant built into the end cover of the gearbox. This was possible because all of the drive chains were on the flywheel side. On the OW1, that placed the kick start lever an inch or so even higher than the F/G31!

Having experience with the OW1, I can say that you do not kick start them while astride the machine. Rather you stand to the side, lean the bike over a little, and kick with your left foot.

-Doug

Offline hazeltons

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Re: Hi Guys.. FACTORY RACER..
« Reply #6 on: 02 Dec 2014 at 11:19 »
Doug, thank you all views i will take on board.... I dont think it's a modified F31 & certainly not a bitza.... It appears totally different..3blade forks, TT carbs & totally different airbox...Special compy Magneto.. FULL RIVITED ALLOY components.. .. I think it's a factory  machine, including correct frame / gearbox / engine numbers..
« Last Edit: 02 Dec 2014 at 19:38 by hazeltons »

Offline Doug

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Re: Hi Guys.. FACTORY RACER..
« Reply #7 on: 02 Dec 2014 at 13:13 »
Steve,

You are discussing items that can be added on to a road bike. While those components might be of racing origin, perhaps even Works, their presence does not make the remainder 'Works'. Initially you said it was definitely a racing model, perhaps a Works model. Now you mention the engine and frame codes prove it is a factory Works machine. Have you received new information that has solidified its provenience? As I mentioned, those codes are assigned to the F/G31 models. Physically the components match the appearance of F/G31 models, as does what can be seen of the gearbox (which you should find a prefix code of AAG/ wide-ratio, or AAB close-ratio.) So far as I know, the codes for the thirties Works racers did not survive, so if you have a source for that information, that would be fabulous addition to the Douglas history.

From what I have seen of photos of the Works racers, and the three or four Works survivors, the frame, engine, and transmission you have do not have the characteristics of a Works racer. By that point what the factory was racing and what they were selling the public was distinguishably different. Deep, finned sumps; reinforced DT/'26TT 3-speed gearboxes (cross-over) followed by a purpose made Sturmey-Archer 4-speed gearbox and external positive-stop foot change; larger heads with wider splayed valves; panier petrol tanks (on the Senior machines); taller headstock, cross-over brake shaft behind (not through) the down tubes (once they went to t 4-speed). Douglas did not go racing with the enclosed valve gear heads, as originally those were configured with a single carb. That would not stop a privateer from putting twin carbs on one and having a go. But back in the day there would have been plenty of ex-Dirt Track Dougies about that would have already been setup for twin carb and high compression, and so would have been less work to go racing with.

There are a lot of Douglas racing replicas about, including several replicas of Works models, so I certainly agree it is worth getting it right. Something about the Douglas make it a favorite to model into a racing machine, and to this day they are popular in a stripped down version with Norton gearbox among the vintage sprinter crowd. You cannot be too careful with your research, as the value between a replica and the real thing is about four to one.

-Doug


Offline cardan

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Re: Hi Guys.. FACTORY RACER..
« Reply #8 on: 02 Dec 2014 at 19:36 »
The most obvious difference between the F31 and the 1931 Works bikes is in the engine department. I don't see anything in the F31 racer engine that looks even vaguely "works". Doug covers many of the differences.

On magnetos, racy Douglases of the period used BTH magnetos as standard, and its likely these were used on factory racers in 1931. BTH introduced their TT and DT Magnetos that year with waterproof but ventilated points enclosures, alcohol-proof windings etc.

Leon

[Edited in response to edit of an earlier post.]
« Last Edit: 02 Dec 2014 at 21:35 by cardan »


Offline cardan

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Re: Hi Guys.. FACTORY RACER..
« Reply #10 on: 29 Jun 2015 at 04:36 »

"RARE UNIQUE 1931 DOUGLAS F31 RACING MOTORCYCLE.. 500cc OHV FACTORY AIRBOX TWIN CARB , THREE BLADE WORKS FORKS"

http://www.ebay.com.au/itm/221812251670

Ah you've got to love the language of ebay!

Leon