My crankcases show signs of the original silver / grey paint. It looks like the same colour as the carburetter body.

Has anyone of you already found out a resembling modern (car) colour? I think it should be a matt finish.

Regards, Michiel

email (option): m.wijbenga@hotmail.com

Same type of paint on several of mine. Others painted OD.

email (option): unpob@yahoo.com

I've never seen any (original) wartime or postwar silver painted crankcases. BSA painted the gearboxes on some models pre war and mid thirties catalogues appear to show some sort of finish on the engines..a sort of Gold colour. However this may have just been in the catalogues as they were illustrations, not photos..
We have established in previous threads that some wartime(the minority) and many post war M20s had engines and gearboxes painted in the appropriate 'green' for the period...Ian

email (option): julie@wright52.plus.com

I should add that I have had a couple of sets of NOS military crankcases and quite a few NOS gearbox cases..all in an 'as cast' finish. I'd certainly be interested to know if a silver finish was ever applied by the factory...Ian

email (option): julie@wright52.plus.com

The WD C10 engines I have, all have traces of silver paint. I think Ron uses wheel silver.

It seems to be applied to prevent corrosion, the alloy is a strange mix, apparently doesn't take to welding to well.......

Yes, I have heard C Models were painted...never seen it (yet) on an M20 though (or B Series engine).
IF they were painted..when and for how long would then the question..Ian

email (option): julie@wright52.plus.com

I concur with Peter. BSA seemed to have used a silver lacquer finish ( like the carb finish) on the C10 range of crankcases and gearbox's. I have found that the best modern equivilent is bought from Halfords and others called "Simonize Five Wheel Silver" In a rattle can. It's realy nice to use but I don't think it will be as petrol proof as the original stuff. Ron

email (option): ronpier@talk21.com

I have just taken a look at the parts list for 1940 contract C6126. This is the only wartime one I have that has 'finish codes' for the different components. Finish is indicated by an extra digit on the part number..ie 66-1234/6.
Finishes listed are as below,but there is no mention of silver paint...

Cadmium../1
Dull Chrome../2
Rustproof Black../6
Black Enamel../7
Khaki Green (No3 Gas Proof)../11

That 'silver wheels' paint isn't even slightly petrol proof..A coat of matt 2 pack lacquer over the silver paint on C10s etc. would be required to give a durable finish...Ian

email (option): julie@wright52.plus.com

I have a several time seen silver painted cranckcases M20 M22 and Mijn M23 1940 has a silver coller paint on it. I always ask myself was it standard on the silver stars?

email (option): indian@inter.nl.net

I've studied the paint closely but it looks original to me, the gearbox is also in the same silver colour. It's quite durable and petrol resistant. It's on a KM21 crankcase for the Dutch army, which is of course prewar, maybe that explains it... In peacetime BSA might had time to paint it.

The bottom of the crankcase is quite badly corroded and I was thinking of applying Aluminium-putty and spray the whole crankcase in the original colour. Michiel

email (option): m.wijbenga@hotmail.com

Ian: what is the difference, visually, between "dull chrome" and "silver"? Could it be the same to the eye?

email (option): jonny.rudge@verizon.net

Hi John..'Dull Chrome' was an alternative, non reflective, plated finish that was applied to some of the steel and brass parts that would have been bright chrome plated on a civilian bike. Also known in the old days as 'camera finish' from its common usage on camera components. It was actually a different process to bright finishing but was chrome.
Visually it looks similar to silver paint but was never applied to major aluminium castings castings...Ian

email (option): julie@wright52.plus.com

Ian, do you have details of the process ? Nobody will tell me how they did it !

The chrome is applied over copper and dull nickel (as opposed to copper and bright nickel.)
Also the chemical mix in the plating tank is different as are the temperatures at which the process is done.. I had it explained to me a few years back at my local platers. I'm due to go in there shortly to see about some anodising...I'll get them to go over it again!!...Ian

email (option): julie@wright52.plus.com