Looking at original photos and restored motorcycles, it looks like there were several styles of gas caps that were used during 1939-1945 BSA M20 production. If so, can you post pictures of the different styles and when they were used?
Were they first nickle or chrome and then painted olive drab during later production?
Thanks!

email (option): questmasters(at)hotmail(dot)com

Did you read the rest of your thread about 'oil tanks'? Ron

email (option): ronpier@talk21.com

Ron,
I did read the reply on my thread for oil tanks. And that is why I started a new thread for gas tank caps. I am just trying to learn and restore my BSA M20 correctly.

So if I understand correctly, the gas and oil cap, both different sizes, were both a plated stamped steel cap with a flat brass winged closure.

The one on the "cut back" late war style gas tank I just purchased, has rounded wings, and marked PATENT 556954 TYPE 42. Is this the earlier 1942 type and not correct for my 1944? It is nickle or chrome plated and I don't want to sand blast it if it is a correct 1942 cap - and just not correct for my 1944 motorcycle.

email (option): questmasters(at)hotmail(dot)com

In the 'production line' picture of late war bikes and this one, it's possible to see the filler cap has the 'angular' T handle and the whole cap is dull chrome plated.

According to what Lex and Henk have discussed, the 42 patented Westwood caps were only ever seen on post war rebuild bikes....I'm quite sure that BSA would not have found the need to buy in caps from another firm.

Henk has a very impressive library of original M20 pictures and he might well have better images than these that I've posted. Maybe you should message him on the subject, in case he doesn't pick it up from hear. Ron

Ron,
I am new to the BSA M20 world and am just trying to learn and find out what is correct to restore my 1944 BSA M20 correctly, and not buy/use incorrect parts.

email (option): questmasters(at)hotmail(dot)com

I absolutely get that, and am trying to help as best I can.....I like the research and find out new stuff all the time... never to old to learn. I still suggest you contact Henk though. He does a dating service (see the home page) and can probably supply pictures of a bike from or near your contract. He publishes his email address on the forum if you 'search' him. Ron

email (option): ronpier@talk21.com

I have contacted Henk and he was very helpful providing date and photo information specific to my 1944 M20. Unfortunately, what I stated with is a frame and rear wheel. I have to purchase everything else - and have been doing just that. But I want to make sure I am buying the correct parts. As I have learned, I have been updating my own site with the information, so that it is searchable and helpful to others.
http://questmasters.us/1944_BSA_M20.html

email (option): questmasters(at)hotmail(dot)com

I don't think your engine is 1939, the number doesn't look like the correct font and is that a drain plug under the crank cases?

Rob

email (option): robmiller11(a)yahoo.co.uk

Well, as I am still learning, all I can tell you about the engine, which has nothing to do with this thread about gas caps, is the engine I have came from BSA 7805, which is stamped on the left case and the rebuild plate on the right side of the head. There is a drain plug (hex head bolt) on the lower part of the left case.

email (option): questmasters(at)hotmail(dot)com

Quest Master (I don't know your real name) You seem to be very defensive about comments made by some of us. For instance you said that your engine is not relevant to this thread, but you linked us to your website! I presume for some critique? Especially after the corrections you made about the Polish markings.

On this site (and many others) the threads can wander off in all directions. No one is out to piss on your firework, just give you the benefit of years of interest and knowledge on the marque. (over 30 years for some)

Happy to help if I can. Ron

email (option): ronpier@talk21.com

That's right Ron, you are about the most helpfull person on this website. :hugging_face:

Thank you so much for all of your assistance and this wonderful forum! I look forward to more information as I learn about the M20 BSA world and the restoration of the M20 that I am working on.

email (option): questmasters(at)hotmail(dot)com