Print Page - B31 Piston identification

Title: B31 Piston identification
Post by: watts on 13 Apr, 2023, 15:56

I have several 71mm pistons, Heoplite and Heplex, I was wondering if there is a document, book or knowledgeable person I could access or speak to to help identify them?
Thank you

Title: Re: B31 Piston identification
Post by: JulianS on 13 Apr, 2023, 16:47

There will be a casting number on the inside skirt.

If you post the numbers someone will be able to identify them from the Hepolite catalogues.

Title: Re: B31 Piston identification
Post by: Oily bloke on 13 Apr, 2023, 19:08

B31 1946 - 1958 Hepolite piston, Std compression which I think is about 6.5-1 number, SW10962
High comp (7.75 - 1) 9939
High comp (9 - 1) 11813
Slipper (12.5 - 1) 10393

Any other number is probably not B31. There are about 20 different 71mm BSA pistons not including oversize.
Hope that helps.

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The BSA Workshop => Singles => Topic started by: watts on 13 Apr, 2023, 15:56