Here’s my C15 trials bitsa. Seems to be trials frame, modified subframe (maybe from road version), ss80 bottom end, alloy barrel, C15t head with valve lifter, bantam wheels (I think). I think the tank may be a genuine bsa trials but not sure. Bought as a runner but lots of issues coming out of the woodwork. Lovely little bike though- I’ve always wanted a bsa trials. When I’m not fixing it I’ll be pottering about on greenlanes.
If anyone knows this bike I’d love to hear from you.