Scott 1912 – Original carburettor

[chstorm]

My 1912 Scott combination has now been restored to former glory and passed the MOT a week ago. It has been registered as A-22 – a period Oslo registration number. There are still a few adjustments to make. The magneto, a Bosch ZE-2, was a bit weak and is now being overhauled with a rewound armature with 10.000 secondary windings instead of the original 7.500. A new condenser which will survive the high frequency voltage peaks in a vintage magneto will be installed. The original mica condensers, not to speak of paper condensers, did not and do not last long.

The main problem at the moment is the original, very complicated Scott carburettor. I could do with some help and/or advice from other veteran Scott owners. I have the spares catalog and the 1912 Scott Owner’s Manual, but they don’t tell me much. Is there a club member somewhere who has worked on such a carburettor before and can share his knowledge? Help really would be appreciated.

Cheers, 😀

Carl

[Erik]

Here some pictures of Carls very, very nice Scott

Cheers,
Erik

[BRIAN MARSHALL]

Hello,
I think that your best bet is probably David Frank, as I know of no-one else with the experience and skills with veteran and vintage carburettors. He more or less made an early Scott carburettor when he did a magnificent job of restoring the 1914 TT Scott for John Bentley. He is a very private person, and does not advertise his skills, and he is not a member of the SOC at present. However I may see him tomorrow evening at our local section club meeting, as we make him welcome even though he isn’t a member ! If he comes I will ask him if he is interested in advising you and/or working on the carburettor, and will let you know as soon as possible.
Brian

[chstorm]

Hello Brian,

I would be very grateful if you could contact David Frank for me. If he is even willing to work on the carburettor, it would be a great help. The parts catalog does not illustrate all the parts, so i cannot even be sure that the carburettor is complete.

Kind regards and thanks,

Carl

[Anonymous]

A very nice bike indeed! I keep my eye out for a pre war Scott but they are certainly a rare beast both on the road and for sale.

Cheers,
Richard

[chstorm]

I have now partly dismantled the carburettor. I found that the jet was blocked, and opened it with a dose of compressed air. It appears that the company where I bought the bike or an earlier owner had not discovered this, and instead had weighted the float down with two relatively heavy flat washers in order to introduce some fuel into the carburettor by overflow. I have not started the bike yet after opening the jet, since I had to dismantle the hand-operated oil-pump. The lower part of the pump, where it is fastened through the frame, had been badly repaired at one time, and oil leaked out to the tune of 2 decilitres per 24 hours. It will be repaired again – this time with a hollow perforated bolt silver soldered in place.
The magneto has now been totally overhauled and is back in the frame and adjusted. Thomas Lindal, who overhauled the magneto had managed to put 12.000 turns of secondary winding on to the armature, and after remagnetizing, the magneto really produces impressive sparks.

A special key of “turn and grip” design was originally provided with the carburettor for removing the jet for cleaning or replacement. Has anyone got such a key? They were, according to an article by Stan Greenway in Yowl volume 5/9 (December 1967) produced by Tom Ward on contract for the Scott Engineering Company. What has been produced once can be reproduced if an original can be found.

Cheers

Carl
😀

[Anonymous]

Hi Carl,

Is the jet threaded into the carb body then, and just cylindrical so a hex spanner will not work?

If cylindrical and theaded maybe a collet drill chuck will do the job, or email me a sketch of the jet and its fitting arrangement and I’m sure we can design a simple tool to do the job if no-one appears with an original tool.

Cheers,
Richard

[chstorm]

Hi Richard,

The jet is only accessible from the top through a small hole beside the so-called “mixing chamber”. Therefore it is difficult to reach it, see it or photograph it. I am afraid that the original tool will be needed to extract it.

Cheers,
Carl

[Author]

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