BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: DAVE BRADY on 20 Mar, 2026, 08:19

Title: C15 gearbox sprocket
Post by: DAVE BRADY on 20 Mar, 2026, 08:19
Hi,


Has anyone ran or runs a C15 with an 18T gearbox sprocket rather than the standard 17T?
The bike will only ever carry the rider and will not carry luggage.  The idea is to reduce the revs/buzz just a bit at 50mph.

Dave.
Title: Re: C15 gearbox sprocket
Post by: rhyatt on 20 Mar, 2026, 09:00
I'm unsure, but is there enough room in front of the current sprocket to accept a larger one.
Could you use if available   a 1 tooth larger crankshaft sprocket, is there more room there i wonder
Title: Re: C15 gearbox sprocket
Post by: DAVE BRADY on 20 Mar, 2026, 09:09
Hi,

The B40 has a larger gearbox sprocket so it should be fine. Changing the crank sprocket is a bit more involved and would affect the kick starting ratio,

Dave.