Bonneville America Forums Forums Technical Forums General Tech no spark - what I've found

Hi all, my 04 Speedmaster stalled while riding home a few nights ago, hauled it home in my truck (thank you wife), and it started when I got home. I didn't ride for a few days, not trusting it until I did some research etc. Reading several posts and having a fair mechanical background, I checked and cleaned - battery terminals, all connections under tank, under seat, inside headlight. Tested female connectors with a pin-drag method, cleaned and packed all terminals with dielectric grease. Cleaned fusebox with contact cleaner, packed with dielectric. Verified kickstand switch had a positive, consistant ohm reading and switched open/closed at the same position on dozens of operations of the switch. Did the same with the ignition switch, and the kill switch. Started the bike, ran for 10 minutes or so, then stalled. Checked to see if fuel was present in float bowls, drained from both bowls in a nice steady stream. Grabbed a new spark plug, checked for spark while cranking at both plugs, no spark present. Allowed engine to cool down, cranked and started after an hour. Figured must be ignitor or pickup coil heating up. Pulled wire connection under seat for pickup coil, connected an analog meter set to 10vac setting, and cranked engine. I had a pulse of apprx 0.5vac while cranking. reconnected wire, and engine started. Allowed to run for 10 minutes, engine stalled. Checked wires from pickup coil again, now no pulse. Removed the alternator cover, gap is o.8mm as it should be. No chafing or open wires I can see. Will be replacing the pickup coil, and will repost my results. Hope these steps might help a brother out who might have similar experience; I've not seen on this forum or TriumphRat that anyone has performed this "pulse" test, I've used it to condemn GM distributor pickup coils many times. Looking forward to riding again.............

Thanks for the update Mike and the comprehensive test process to find the apparent fault. Looks like you've taken the guess work out of the pickup coil replacement. Did you notice if the resistance of the coil changed from when it worked and when it didn't? How did you manage to get a pulse voltage reading. Digital voltmeter with peak hold or did you use an analog meter?

Gregger, I didn't check the resistance of the pickup coil, figured the pulse was a better check. I used an analog meter set to 10VAC, the pickup should send 2 signals per crankshaft revolution by the magnets set into the alternator rotor. The pulse is about .5 volt, meter should "bounce" a bit. After the engine stalled and I checked right away, no "bounce" on the meter. After I removed the pickup, I waved a magnet over the coil core, and again had pulse. This was about 1/2 hour after the engine stalled. Never did check the resistance, may try that in a pot of hot water to see what temp it opens up at.

Ok, update. Put the pickup coil in a water reservoir, heated the water while watching the resistance across the leads. Started out at 601 ohms at cold tapwater temp, went open circuit (infinity) by about 130 degrees F. I say about 130F because while the water was hot, I could hold my fingertip in the water somewhat comfortably. Pulled the sensor out, dumped cold water on it and immediately went back to 600ish ohms. I have to assume since the alternator is wet immersing the sensor in water to test shouldn't hurt it..........

You got it nailed. Glad you were able to confirm the coil is the culprit. Placing the coil in water shouldn't be an issue either.

Thanks for the update.

Checking the coil in heated water is pretty clever, kudos to your diagnostic instincts.

Thanks, I stole the heated water idea from the T-Rat forum, was sure glad to see the thing go open circuit with a raise in temp, just to reconfirm my test was accurate. Now to get a new pickup - appear to be backordered until May 30th..... Anyone know a dealer offhand with a big inventory? Haven't had any luck with the 3 I've tried (2 local and 1 in Jersey).

Good work. This diagnosis belongs in the vault.

Nice going, Mike... absolutely brilliant! This thread is a help to us all!!

Tech Vault entry.

great write up. i'll be testing to see if i get a pulse on my pick up coil tomorrow. my resistance seems to be with in range at 592 when cold but no spark.

mike, any ideas on how one would test an ignitor if possible?

Once I received the new pick-up coil, I put my digital meter on it to see if it would show any resistance. It, as well as the old one, did not. I switched the meter over to 200k (I think), and it did show resistance of like .005 or something. Placed same on old pick-up, and it too read the same reading. Attempted to heat old pick-up, no change, still read same resistance as the new one. Was convinced this too wouldn't fix my bike.
Went ahead and installed the new one after measuring original gap, replaced gasket, and she fired right up, and ran as stated above.
Parked bike until new Triumph shop manual arrives Wednesday to make sure pick-up coil is installed correctly.