August 27, 20188 yr Does anyone know the thread types/sizes on the Cub engine? I'm particularly interested in the fasteners that attach the gearbox casing to the crankcase. On my engine I've dispensed with the outer cover, meaning I've got 10 2BA screws of various lengths, plus two larger diameter screws at either end of the casing. These are the two I need sizes for. Many thanks.
August 28, 20187 yr Unfortunately the British Motorcycle Industry had access to many types of threads, BSW, BSF, BSC (cycle) and of course Unified. At some stage all of the aforementioned may have been used on one type of bike or engine or both and this makes selecting replacements difficult. Possibly a reason why no one has responded with an answer. A thread gauge will only be of use for bolts and some nuts. One solution might be to drill out the unknown gearbox to crank cases threaded holes and tap them to a known size, not a hard job to do if done with care and planning. At least you will be able to have a choice of fastener types and this wouldn’t detract from originality.
August 28, 20187 yr Author Thanks for your reply Section Swept. I've been told by a Cub expert that they are 1/4 BSF. I've ordered a tap so hopefully that will solve my problem!
August 28, 20187 yr 1 hour ago, RichardH said: Thanks for your reply Section Swept. I've been told by a Cub expert that they are 1/4 BSF. I've ordered a tap so hopefully that will solve my problem! If it all goes pear shaped there is always the option of thread inserts.
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.