Wiring

[PatrickO]

Can I ask for advice on wiring.I'm about to start rewiring my 1970 A65, but the wiring from the engine casing doesn't seem to match the wiring diagram.

My workshop wiring diagram shows one wire from each side of the engine going to the coils.

However, on my bike there are TWO wires coming from the left (primary) side. Both yellow/green for what it's worth.

Can anyone tell what the two wires should do?

BTW it's points not electronic ignition.

[cornishbob]

the first thing i'd do is find out where they originate from

[DAVE BRADY]

Hi,

The wires from the primary side will be from the alternator. Two wires for the 12v system on your bike. They are shown as green/yellow and white/green in the wiring diagram.
The coils will have a white wire bringing power from the ignition switch to the '-' terminal and there will be a black/white wire to the '+' terminal of one coil to one contact breaker and black/yellow from the other coil to the other contact breaker.
What manual are you using?


Dave.

[PatrickO]

Hi,

The wires from the primary side will be from the alternator. Two wires for the 12v system on your bike. They are shown as green/yellow and white/green in the wiring diagram.
The coils will have a white wire bringing power from the ignition switch to the '-' terminal and there will be a black/white wire to the '+' terminal of one coil to one contact breaker and black/yellow from the other coil to the other contact breaker.
What manual are you using?


Dave.

Thanks Dave. That's very helpful. I'm very new to motorcycle electrics so it's quite a learning curve.

I'm using the BSA Workshop Manual for 1969-70 650cc and 500cc twins. 00-4177 November 1969.

[DAVE BRADY]

Hi,

Some non BSA manuals can be inaccurate but you have the right one.
Whilst doing the rewiring it may be worth using a modern rectifier/regulator instead of the Zener diode and rectifier.

Dave.

[cornishbob]

surely its better to learn by doing not looking at the book but then i'm good at learning quick

[PatrickO]

Hi,

Some non BSA manuals can be inaccurate but you have the right one.
Whilst doing the rewiring it may be worth using a modern rectifier/regulator instead of the Zener diode and rectifier.

Dave.

Thanks Dave. Useful