Help with Ignition Issue

Need some help trying to diagnose an ignition issue with my 72 Roadster. Bike has a Tri-Spark EI and a modular 12v coil (Dual Fire Power Arc from Old Brits). Earlier this summer I got caught in a huge downpower. Bike never hiccuped during the episode but when I went to start the next day it ran for a couple minutes and then shut down - no spark. Did the same thing the next day. Figured it was a moisture issue and low and behold after a few days it started and ran fine... until got a few miles from home and it shut down again. Waited 15 minutes and it started and got me home. Since then it has not started. I get a good health spark for the 1st couple kicks and then it fades until no spark after 4 or 5 kicks. Turn the ignition off wait 30 seconds and I get good spark for a couple kicks and again fades to nothing after 4 or 5 kicks. Checked the wiring to and from the EI and it is fine. Replaced the coil with 2 6v coils with no change. Battery appears to be fully charged.

Any ideas why the bike is losing spark after a few kicks. Could the Tri-Spark be the culprit? I have never had an EI fail so not sure what the symptons would be. Any thoughts/suggestions would be appreciated.
Jim

It sounds like the tri-spark has failed. Of course I would suggest checking it by running a hot wire directly from the battery to eliminate connection/switch problems. Are you sure the power arc coil is compatible with the tri-spark? That could cause a module failure. There is a lot more to a coil than just matching the primary resistance . Jim

in addition to comnoz's suggestion to run a wire direct from the battery...

I would also verify the trispark ground integrity, as in test the tightness of the little bolts holding the trispark in place as it is self grounding in that respect

I have a Trispark also and shortly after I bought it a couple of years ago, like you I have intermittent running along with just shutting off, it turned out I needed to more strongly ground both the motor and my battery

so I took some nice thick wired and ran it from the back left sie motor mount down to one of the oil filter bracket fastener bolts, then ran another thick piece of wire right from the positive battery terminal again down to that oil filter bolt

trispark intermittent problem solved, it has run absolutely flawlessly ever since

When was the last time you cleaned up-tightened the groundpoint to frame? Clean up fuse area too.

Is your Tri-Spark being powered through the handlebar mounted kill switch ? If so, this could be your problem...My TS was wired that way and started giving me problems and it turned out to be the contacts in the killswitch. I rewired the TS directly to a switched hot wire off of the key switch and no more problems.

My buddy also had problems with the Boyer on his Commando and it also turned out to be the killswitch and we re-wired it directly to the ignition switch which also cured his issue.

Thanks for the suggestions. I will try the hot wire idea and also check the EI module ground and the engine to frame ground. The bike does not have a kill switch.

Hi

My First Tri-kick behaved as you describe.
I contacted the manufacturer in Australia and described the problem.
He sent me a new module free of charge

Vidar

Vidar - How long after the installation did the problem occur? This unit has been in use for over 3 years.

If a boyah first thing I'd check is broken copper inside trigger wire insullation so might flick at those with a plug out to see if sparks w/o runing to id a part in the chain that can fail. If whole system power blanks out check tail light to head light area. I always feel pensive after a show stopper fixed and heading out again.

Checked the EI module ground and the engine to frame ground - no change. Hot wired the unit direct to the battery and no change. Noticed that when I turned the key switch on the EI module red light stayed off. When I started to kick the engine over the red light came on and stayed on. After 4 or 5 kicks the spark faded to nothing. I am guessing the Tri Spark unit has failed.

Ugh only one sure way to find out now. Its not a bad id to keep a spare ign on hand along with other failure prone items. Hope nothing changed in the trigger mounting hardware area. If so a new one may not do it.

Hi again

Think it was ca.to years.
There was no questions. Think this was a typical failure of the "old" modules. The new should be more resistant to heat and vibration.
The new I've got has worked perfectly.
Vidar