BSA Owners' Club Forum

The BSA Workshop => Twins => Topic started by: Steve Tipper on 22 November, 2017, 19:44:01

Title: Identifying the age of a unit bottom end.
Post by: Steve Tipper on 22 November, 2017, 19:44:01
I've got a unit twin bottom end which was purchased from a breakers.
There's no engine numbers stamped on and no sign of foul play either (no sign of numbers being removed)
It's substantially all there  with only the primary outer cover and outer timing cover missing.
I'd like to get some idea of the year of manufacture based on the features present.
Possibly a pointless exercise because it may be a complete mongrel itself but here goes.
Crankcases have 5/16" barrel studs.
Alternator stator mount is the cast alloy type.
Gearbox filler on crankcase
Timing plug plate front of TS crankcase.
The inner timing cover has the early type clutch actuation
Speedo drive bulge on the casting but not machined out.
The clutch is a 3 spring type.

Working from Roy Bacons restoration book I'm thinking about 19966-67 maybe ?
Any other opinions welcomed.
Title: Re: Identifying the age of a unit bottom end.
Post by: JulianS on 22 November, 2017, 20:58:59
Post some photos we may be able to identify.

Any casting numbers?