Super flash fuel tank difference

[coater87]

 Out of curiosity I looked at a super flash tank and noticed a big welded on mount in the back (this was a plunger model).

 Also noticed a vent and flipper gas cap.

 I doubt the mighty BSA actually made special tanks for these, so what tank did they modify?  Does anyone reproduce it?

Lee
 

[BSA_54A10]

Special tanks for the USA
East coast & West coast were usually different
Tanks with flip caps & vents were usually fitted to Gold Stars and some A 10 spitfires
You will not find any mention of them in BSA parts books only in dealers supplimentry parts lists issued by the distributors.
Falco did mention them in his Gold Star Buyers Guide and some of the dealers parts lists were reproduced in edition 7

BSA made their own tanks
Most of them are one of 4 different top pressings, cut at different angles to make different capacity tanks
We were going to start making them by explosive forming and when I made casts of the different tanks I had this became very apparent   
Press dies are ery expensive turnng 3/4 of the pressing into scrap metal is a lot cheaper than making a dozen different dies .

[bikerjohndavies]

The tank is listed in the 1949 to 1953 A10 Parts book Superflash supplement as held in the Service Literature, Scans, Links, Documents section of the forum.

https://www.a7a10.net/forum/doc/parts/BSAA7_A10_1949_to_1953_Spares.pdf

Here is a scan of the relevant pages. The 67-8114/19 is matt silver on chrome lined in red and the 67-8114/38 is the metallic green on chrome lined in dark green.

[coater87]

 So if I am understanding, these 700 or so Super Flash bikes had their very own tank shape. I would have thought for sure they just modified an earlier tank by brazing on the tail piece.

 That had to be an expensive tank to produce.

Lee