1972 A65 wiring

[Mezzman3]

Got my A65 oif all wired up everything working as it should then I wired in my boyer ignition  which also appears to still work. Then I wired the coils  in and this causes the indicators to flash faster probably over 120 a min. Disconnecting  one could wire makes them slower. I dont yet have the engine in the frame but I dont think that should matter tbh. Any help would be great thanks

[Allan G]

Have you wired the ignition as per the bsa wiring diagram or the Boyer wiring diagram? Can you post some photos of under the seat also?

[ChrisG]

Did you disconnect the coils and try again? Reason for asking is the flasher works on the principle of the load on it. The load is the wattage of all the bulbs 2X21W and a 3W warning lamp. If a bulb has gone or the connections faulty, it will flash quicker, which is a good warning that a bulb has gone.
If you did disconnect and all is well, then I would ask the very helpful guys at Boyer. They are really clued up!

[Allan G]

Reason for asking is the flasher works on the principle of the load on it. The load is the wattage of all the bulbs 2X21W and a 3W warning lamp. If a bulb has gone or the connections faulty, it will flash quicker, which is a good warning that a bulb has gone.

You would think so but this isn't the case. I think this is only with the 3 wire flasher units. If you completely detach an indicator wire then the other bulbs flash at the same rate.


I suspect there is something a miss with your wiring for the Boyer box, possibly a bad ground wire. It could also be a bad feed wire through the kill switch on the handle bar.

Any electronic ignition requires a perfect wiring system otherwise it will start having problems. The kill switches on these bikes are prone to being weak and breaking down, a push to make type kill button is much better and can be used. The normal type is a push to break type kill switch, because it's a constant feed arcing occurs and increased resistance will cause a sensitive electronic ignition to start breaking down.

If you have wired your bike "correctly" the white wire with yellow stripe coming from the switch will plug into the white wire of your Boyer ignition box

The black wire goes to the negative terminal on the nearest coil, a short wire (either black or red of your own making) joins the positive terminal on that coil to the negative terminal on the next coil.

The positive terminal on the last coil not only connects to the red wire on the Boyer but should also to a good earth point.

The earth point is usually where a lot of problems occur. However. If you have 1 post (bolt or stud) mounted on a good grounding area (the original rectifier post is idea if you have a modern Reg rec) all your red wires can bolt to this (so coil wire, Boyer red wire, reg rec red wire, and a red wire back to the battery) this should solve most if not all issues.

I mentioned earlier about changing the kill switch setup. You will also improve the feed to the Boyer....

The white with yellow stripe wire connects into the switch wires under the fuel tank. Remove the white yellow from the corresponding wire on the switch and plug it into the white wire with red stripe going to the switch.

At the other end under the seat, connect the wire (you might have to change it to a spade connection) and remove it from the Boyer box and connect it to one of the negative terminals on the coil (on mine I have connected it to the first coil fed from my ignition)

At this point the Boyer box has no live feed to it. If you have a spare terminal off position 1 on your key switch connect the white off the Boyer box straight onto here (or if there isn't a spare terminal at position one fit a piggy back terminal or crimp two wires together.) this way the Boyer feed is as close to the battery as possible, the only break down point now is the key switch, instead of the key switch and the handle bar switch. When your press the other button (which is now The kill button it will interrupt the pulse going to the coils and the box will act as though the engine has stopped. Note the coils only spark when the connection is "Broken" so when you switch your key off you get a random spark, not when you turn it on. The points wires are simply breaking and making this connection doing the same thing but to a timed event.

[Mezzman3]

I have the bike wired as per drawing and the boyer box wired as per instructions and I have a spare terminal at pos 1 currently the red/white wire Is taped up and redundant so all i need to do is swap that for the white/yellow and power from key switch? I have the 2nd coil earthed to the battery  terminal  is that okay?

[Allan G]

Yes, but you would also need to connect the white/yellow wire to the negative terminal on the coil closest to where the black wire from the Boyer box plugs on. Then white wire from the Boyer box to pos 1 on the switch. You can check it's working by resting the plugs on the head whilst connected to the ht leads, switch the key to the lights position slowly and the plug should
Spark when going between ignition onto the ignition and lights, then turn it back to off and it will spark twice, same spot again and as you switch to off. Then do it again with the right hand top button (same side as your indicators so if they are on the left cluster it becomes the bottom switch) and turning
The key in all positions will not spark at the plugs with this pressed in.

Red going back to battery is fine as long as: the Boyer is connected to that last coil on the red.... and you have a good engine earth between the motor and the battery terminal (the coils need a good earth to battery to complete the circuit)

I modified the wiring diagram for when I built my own loom recently, I'll have a look for a digital copy of it tomorrow and post it on here. There is also a modification to the lighting circuit on there.

[Mezzman3]

Thanks very much I will try that as soon as I've solved my clutch issue. This bike ran with the boyer unit wired us as is with no problem  in the mid eighties  and with the same loom which I unwrapped and checked and re wrapped  and the only problem  I had initially  was the kill switch wire was trapped behind the contact in the handlebar switch causing a permanent make. After several start from the beginning  and re connect everything late  nights I found the problem. Wiring is not my best forte