I have a 73 Norton 750 Commando that I completly restored from the ground up. The previous owner installed a boyer ignition system so I used that. The bike now has only about 100 miles on it and the least little bit of contamination on the spark plugs and it will miss fire and pop and back fire. I'm talking a little bit of carbon or soot. I have had to clean the plugs 5 or 6 times now and then it will run great, for a while. The engine is running just slightly rich and for now, I just as soon leave it that way. If I take a plug out and hook it to the spark plug wire and kick over the starter, the spark seems very weak and erratic. The battery is fully charged and the plugs are NGK BP7ES. I am told these are the cross for the originals, but who knows? The coils are new and the same size as the originals and are german made and 6 volt. They are wired as Boyers instructions. + of one coil to ground and - of that coil to + of the other coil and - of that coil to the boyer box. I did make the plug gap slightly smaller and this seemed to help. Anyone out there got any ideas?? Thankyou
You say the battery is fully charged,but is it in good condition? Boyers are very sensitive to voltage.The battery should be between about 12.5 and 13.8 volts with the ignition switched on.Lower voltage will give problems and higher voltage will damage the unit. Boyer have their own web site dealing with this so if you need to you could have a browse. Don7.