with a chair attached ? did you not need a licence for a 500 bsa in 1970 , forgot to ad let me know if you need anything I have quite a few parts , bomber if you must have a B33/31 (don't know why as the side valve Norton is better) get the swingarm B33 pre full width ariel hubs , its the best of the bunch , B31 is to slow , but better still get a Ariel far better bike I think