BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: Jerry on 20 Jul, 2019, 19:22

Title: Fuse
Post by: Jerry on 20 Jul, 2019, 19:22
Hi everyone just joined today and would like some help.
We have a Starfire and it's blowing the fuse every time the battery is connected.

Any ideas why this is happening?


Cheers
Title: Re: Fuse
Post by: chaz on 20 Jul, 2019, 21:57
battery connected the right way ...pos earth?
bad earth connection
dodgy worn wiring or old terminals
burnt out components..


time to get the circuit tester out
Title: Re: Fuse
Post by: AdrianS on 21 Jul, 2019, 14:06
Is it blowing the fuse when everything is turned off including the ignition ie is the fuse blowing when just connecting the battery?

There is obviously a short somewhere. You need to start disconnecting circuits to find out. Not sure with the Starfire; has it got a plate rectifier or Zener diodes? I would check there first unless there is an obvious short somewhere else.
Title: Re: Fuse
Post by: A10 JWO on 21 Jul, 2019, 14:39
Start with a wiring diagram, sounds like a dead short. If it is the old loom probably a broken wire. This normally happens when there is a large group of wires like inside the headlight or the ignition switch. Consider a new loom about £45. Much easier than rebuilding an engine. Bring it round my house : )
Title: Re: Fuse
Post by: Jerry on 21 Jul, 2019, 21:22
Hi

Yes the fuse blows when everything is off and we just connect the battery.
The previous owner had fitted a new loom but said he burnt some wires when he went to charge the battery. We had it running when we went to see the bike but on the 3rd time of going to start it the fuse kept blowing.
Title: Re: Fuse
Post by: chaz on 21 Jul, 2019, 21:50
MY A10 chop has a stainless battery box and custom loom, somehow (probably as fed up with wet sump and or flat battery) I left the lid loose.
it dropped down onto the battery and burnt the Earth from battery to Frame, then the earth to rear light. also melting the other two wires in the light loom. no other wires from switch to ignition or front end were effected. Fuses did not blow as ignition not on.
today have re made the back end wires..
careless, could have caught the garage on fire!!! lesson learned.

I suspect your wires are melted and touching inside loom.
Title: Re: Fuse
Post by: Jerry on 23 Jul, 2019, 17:58
Thanks for all the advice, so far we have found a burnt out wire.

Can someone advise us on what way the ignition barrel should be wired up.
I can see 3 connectors marked up

BAT
IGN
ST

Cheers