Where to find a set of coils.

[Lou]

I have a 78 750 and 2 of the spark plugs just stopped firing when you put the plug wire on the plug tried everything I can think of even jump-firing it to make them run, well that worked but I am in search of a set of coils now but can't find it at the local shops. it cuts out and is very hard to control at slower speeds.

[Rich82GS750TZ]

Which 2 plugs? One coil fires plugs 1&4, the other coil fires plugs 2&3. Cylinders are numbered 1234 L to R as you sit on the bike.

[Lou]

it is the 2nd and the 3rd. Checked connections & fuses already. Here are things I was told till now, it's the carb adjustment, bad fuel delivery or it might be the bad coils I have tried everything so far but all in vain just tried installing an old but working coil but nothing. fuel delivery is ok. will check the carb adjustment and the strange thing is the bike is running fine at 5K or above RPMs.

[Rich82GS750TZ]

So the coil that fires plugs 2 & 3 magically starts firing above 5K RPM?

Does your bike have the original points ignition or has some replaced it w/ electronic?

[Lou]

Strange, isn't it??

The points are original and ok to use. Changing Dyna electric ignition mod help here?

[Rich82GS750TZ]

All I can tell you is people here have changed over from points to electronic ignition. Don’t know if that will solve your problem. Could be the plug wires are bad on the 2/3 coil. Dunno. You’ll have to wait for someone with more electrical diagnostic skill and experience to chime in.