I think that this is a BSA A10 Super Rocket, but I’m no bike expert, so could be wrong. Please feel free to correct me if so. 🙂
The shot was taken at a steam rally last summer (I posted about it a couple of times here & here but never published this particular photo).
Olympus OM-1, F.Zuiko 50mm f/1.8 & Fomapan 100.
Taken on 25 June 2017
Steel City Snapper photography 