I am restoring a 1962 BSA Super Rocket (US version) and this is my first post. It appears that my bike is the Big Valve model with 1.5” intake valves. I think the part number is 67-0691 but this number is not in my parts book and I ordered the wrong valves. Is the Big Valve version rare?
Thank you for the info. The Big Valve Head is a very strange beast. I ordered a new 389 Carb based on research although another carb appeared to fit slightly better and hope it will work. Some feel that there is actually no such thing as a big valve and that it was just a marketing ploy by BSA.