Ignition problems?

Not open for further replies.
Apr 15, 2007
After letting my 1971 commando sit for a month I tried to kick start it to no avail. Found the battery to be dead, Recharged it and still nothing. The bike was converted to a boyer ignition before I bought it. Could the boyer have gone bad from low battery voltage? Should I start by pulling a plug and checking for spark? Any help would be appreciated.

Thanks, MIke
A flat battery can't have hurt the Boyer. What battery volts are you getting now ? If one cell has gone down, the volts could be too low or you could have a co-incidental problem (I find Commandos are quite good at that :) )

Try resting a plug on the head and turning the ignition on and off. A Boyer should give you a spark when you do this.

If you're intending a long-term relationship then the purchase of a multimeter would be a good idea, even just for measuring battery volts and continuity.

It is quite possible that you have a 'dry' connection somewhere or a bad switch contact. If the battery is in order then the next step is a temporary 'hot-wire' from the battery to the coils.
The Boyer needs a good voltage supply to work properly.

You certainly need to check that the plugs are sparking, although the problem may not be the Boyer itself but more likely a bad electrical connection somewhere?

But the first thing to do is to check the battery, is it in good condition and capable of holding a charge properly.

Boyer fault finding sheet: http://www.boyerbransden.com/html/fault_finding.html
Step one take the battery out . Go to a place that has the proper load tester and have it load tested. Just because it reads 12 volts after charging doesn't mean it's good. A crude test can be done at home turn on the headlight for two minutes then without turning it off do your volts test if it is not 12.5 or above the battery is toast. New battery's should also pass this test if they don't take them back you won't be the first.
Once the battery is proven good you can do some simple tests. Run a jumper wire to the power wire on the Boyer from the negitive battery terminal. (assuming positive ground system) This will bypass the key and the kill switch the next most likely suspects in the no spark situation. To test for spark take an extra set of plugs and ground them to the head with the spark plug wires on them. Wires with clips on each end work well. You can just hold them on the head but you could be shocked. Kick the bike you should get a spark at the plugs. If not you can test the boyer and coils by forcing a spark ,a short wire bared on each end that can connect the two coils under the points cover briefly will make it spark at the plugs. If that doesn't work the Boyer or the coils or their wires are at fault.

here is tip for electrics per John Healy :

replace the fuse with a small light bulb. begin to disconnect one item at a time, headlight, tailight, etc.....when the bulb goes out, you found your short. Repair short and replace fuse....
Not open for further replies.