Intermittant spark on one side - Thunderbird Triumph Motorcycles

If you are experiencing an intermittent spark, you may be having problems with the magneto / coil (ignition module) or CDI box if so equipped- that produces the pulses of high voltage for the spark plug; you may have damaged spark plug wires that are shorting out- check the resistance (using the Ohms setting on a multi meter) on the wires; and check to see if your ignition module is producing a strong spark...check the resistance on the primary & secondary coil. Or you can use an in-line spark tester- the tester is inexpensive and you can buy it at any diy auto parts supplier.

how good is the magneto on it? just a guess but it does create the spark

Sounds like your coil has gone bad, usually when a coil fails the symptoms are as follows: intermittent spark when engine is hot, then no spark until engine cools down, and eventually no spark at all.

the P0303 code is for cyclinder #3 possible causes: -defective spark plugs, ignition cables, ignition coil. or flywheel/pulse wheel. -blocked/leaking injector -uneven compression -leakage between the cooling system and cyclimder moisture,flashover in the ignition system on HT side intermittent open-circuit, intermittent short circuit to tje ground,intermittent short circuit to the voltage supply, contact resistance or loose connector in the ignition system low-tension side, in the injector circuit or fuel pump circuit -fuel stoppage -water in the sparl plug wells - contaminated fuel or incorrect fuel type -repeated cold starting where the engine coolant temperature (ECT) has not reached nomal operating temperature between start P0304 is for cyclinder #4. Hope this can help you, please put some rating

most likely the ign switch is ok if you are getting spark. so you have a hot spark at coil and weak fire at plugs? if you have a test light check the positive side of coil for power when turning key on and cranking. if it is dropping power on positive side then ign switch could be bad. can "hotwire" coil by jumping a wire to positive side of coil to pos of battery this will eliminate ign switch.

prob the coil or cdi unit both control the spark

well i would start at the electronic spark controller when they get hot they can couse this issue replace them all the time it is at the right side of bike down in the in front of crical cover that what it sound like next time you can get this to hapen pull plug wire see if you have spark no spark then the module is it most likely or coil but replace more module then coils

Replace the TFI module. Google Ford TFI modules and you see the problem they have with these.

See if the spark will arc across the area where the pilot flame is. It should cross the flame. Adjust the spark if possible.

Hello
Check and make sure that the electric sending units to the side that it's not sparking ( Left side or Right side) are good, you can check that by replacing the one that works with the one that does not. they are located under the knobs on the switch rod, it's very simple, they just sit there with 2 wires, just lift and unplug the wires and replace with the good ones, and if they start clicking when you turn the knobs, then just replace the bad ones with new ones.
Hope this help
Eddie Rentas
Tupper Lake NY