Ignition coil failure symptoms

What are the common symptoms of an ignition coil failure on a running bike? Running bike as in can be started, and drives. Are XJ coil failures common?

 

Sympton; My bike quits running when I ride in the rain.
This is caused by the case cracking. It lets moisture(rain)in then the coil stops working.
Broken or weak plug wires wil cause a poor running engine.

Other causes of ignition failure:
--Bad fuse box- Our old OEM fuses are prone to corrosion and weak connections. Replace it if yours is original.
--Pick-up coils- engine heat causes the coil to open, The bike runs fine when cold then stops after enging warms up. Same thing can happen to the TCI.

 

Pick up coils...is this a common or even an occasional failure item on the XJ's? When they heat up they can stop working or work poorly until they have a chance to cool? Would a pick up coil failure stop the engine or just cause it to run poorly?

 

Pick-up coils is not a common failure but it can happen. Most of the time the wiring connections corrode and cause problems. When one stops working for whatever reason , you will loose 1 ignition coil and the engine trys to run on 2 cylinders.

Tell us exactly what symptons you are having with your bike. There are a few things that must be in order before it will run correctly. Valve clearence and carb top the list.

 

Yeah, I've been working with this forum for a spell trying to get my XJ running well, and best I can tell and with backup from any feedback, my problems appear to be carb related. I have done about everything to this bike to get it to run well dare I post the list including checking and adjusting valve clearance and installing new correct sized jets. The latest update is that I had set the float levels to exactly 3mm (OK, +/-.5mm) and re-synched the carbs, things are working better now, very much so at high engine speeds, however the bike is running rough at idle and slight throttle once warmed. Also, although I have not calculated my mileage based on fuel in tank and miles ridden, I look into the tank after about 60 miles from full tank, and it appears that I've used about 2 gallons of gas. Still running excessively rich I suspect. I am now looking for less likely candidates to check and blame and fix. For instance, pick up coils or maybe the PO drilled out the emulsion tubes? Very troublesome this bike has been.

 

Use an OHM meter and verify all your coils are good. Check for cracks, too.
I have a set of cracked coils that I repaired with Liquid Electric Tape and they work fine.

 

I have gauged the coils, wires and caps and all read good according to manual specs, also inspected, cleaned and coated all the electrical connections with dielectric grease. Do you suspect that a coil could fail when hot, and return to proper reading when cold?

 

make sure pilot screws are adjusted right. i bought my bike running rich way rich like 20-25 miles. it would foul plugs. it was cause by the pilot screws. they have different setting for diferent years and carb types. the guy i bought my bike off set my bike for a older syle xj with reguler threaded pilot screws. so when i checked them they where 6 screws out. when they needed to be 2 1/2 to 3 screws out. my bike has the micro threaded pilot screws. hope this helps sorry i didn't see post sooner.