B40 engine number query

[chaz]

trying to mix and match the mongrel B40 I know its a 1964  frame but have a problem finding the year for the engine.
its a B40 FB 725, I see from various charts a 1966 was a straight B40 **** and a 1967 was  B40 G 201 onwards.
any ideas what the FB is for as the end of production letters does not tieup with an F and B in that order.

[chaz]

just poking around on a new set of numbers the FB would have been a Sportsman USA model, both engine and frame are 1965 year.
wondering which parts book to use, Ive got copies of the ES Enduro star and the SS Sports star. the SS also notes SS USA.
can I use the SS book for the Sportsman model?

[JulianS]

The 1965 B40 parts book in the Club members area covers the B40F B40FSS and B40FB models.

[trot]

The engine number no my B40 is 1200 can you please tell me what year it is. Thanks