BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: Rodger Ramjet on 30 Oct, 2025, 10:40

Title: C15 electrics
Post by: Rodger Ramjet on 30 Oct, 2025, 10:40
Good evening. I've just brought my c15 out of moth balls after approximately 10 years. I'm not sure if I have a short circuit problem or this is typical of a 1963 bike.
As soon as I connect the battery I can switch on the headlight,which in turn puts on the tail light and also the horn works . The bike won't start until I switch on the ignition.
Is this normal bsa running or do I have a live wire connected to the frame somewhere?
Title: Re: C15 electrics
Post by: Barnsey on 30 Oct, 2025, 10:44
My new purchase appears to be the same.  Indeed the previous owner has fitted a kill switch to isolate the battery and save it going flat.
Title: Re: C15 electrics
Post by: JulianS on 30 Oct, 2025, 11:05
Sounds like the way it should be. The ignition switch has 3 positions, off, on and emergency start. It does not control/switch on or off the lighting, horn or stop light circuits, they work independently of the ignition switch.
Title: Re: C15 electrics
Post by: limeyrob on 30 Oct, 2025, 11:17
Agreed, sounds right.  If the 50's it was a legal requirement so show lights when stopped at night so vehicles were made so you could operate the lights with no key.
Its the Road Transport Lighting Act 1957 but it lead to so many flat batteries and was very unpopular so it got phased out in the 60's.
Title: Re: C15 electrics
Post by: Rodger Ramjet on 31 Oct, 2025, 20:57
Thanks very much for the input, everyone.
My boss at work is an auto electrician and he said as much.
Now I think I will have to fit a kill switch somewhere on the bike.
Title: Re: C15 electrics
Post by: rhyatt on 01 Nov, 2025, 08:35
You already have a kill switch, namely the ignition switch ,
The only thing you need to consider is the fitment of an inline fuse between  the battery and earth.
Unless you're likely to leave the lights on or the ignition on yourself (visible by ammeter discharge)