BSA B25 - If the picture on the right is of the concert promoter zipping around like i've seen in the film. Likely a '68 or '69. I have a '72 and they didn't change much. Yellow and bare aluminum gas tank. Some leftovers in 1973 were sold as Triumphs too.
I'm thinking it was a BSA 441 Victor Special. I don't recall any other BSAs with that distintive yellow paint/aluminum tank.
