Spark plug leads - how to test

On my 97 Trident, I'm trying to work through some spark issues. I've tested the coils - they seem ok. Spark plugs will be replaced this weekend.

Mystery: I tried to test continuity on all 3 leads, one test lead on the coil, one test lead at the spark plug connection. On all three leads, I get no continuity. Is there some magic I need to know about these leads?

Thanks,
Dan

[trypcil]

Whats the ignition issue? Hows your tachometer?Turn the meter on, or maybe they're transistorised?! How did you test the coils :razz:

Yep, I checked the on/off to make sure the meter was on and functioning, and touched the leads to verify functionality.

The performance issue is symptomatic of a bad coil:

Drives ok until the bike warms up, then performance deteriorates to sputtering.

I put a timing light on each plut wire and the #1 plug lead was very sporadic - mostly not firing. #2 and #3 looked ok.

I followed the Hayes book coil testing steps for both primary and secondary circuits with no problem - all in spec. I tested the coils cold, not while the bike was hot and sputtering.

I've had spark plug wires/boots go bad on older bikes, but these wires don't seem to be like old bikes. No continuity at all from the coil end to the plug end on all 3 wires. The Hayes book makes no mention of anything "special" about the plug wires. Anyone got a Triumph repair manual handy?

Thanks,
Dan :???:

Ok, I feel dumb, but I learned something.

Spark plug wires are made with a certain amount of resistance, which has something to do with radio waves/interference.

I don't have triumph numbers to compare against, but I did find out that all my plug wires have just under 5k Ohms resistance.

Now, I still don't know why I don't find simple continuity, even though there is resistance, but I can live without finding out.

Now I know my coils are good and my wires are probably good. All is not wasted...

[j98sprint]

To test an HT lead ( spark plug wire) unplug it from the coil and pop the other end off the spark plug. Put one lead on one end of the wire and the other lead at the other end of the wire. Set your VOM at 20K or 50K ohms and you should see less than 5K ohms. I tested all three of mine and they all showed about 4.7K ohms.

Let us know how this works out.

j98sprint

[triple900]

The reason for the high resistance in your wires is that you are putting thousands of volts through the wires, if they were .02 or.03 ohms like a normal wire, they would turn to smoke and ash.

[DAGAD]

Hi Guys, just checked out your pages and found I have / had similar problems with my '92 Trident. For no apparent reason, suddenly goes onto 2 cylinders :???: Then when it feels like it, back onto 3 again?
seems to be No.3 (r/h) but sometimes No.2 To date I have replaced: ignitor box, plugs,coils and leads! The problem goes away and just when you think it's cured.......onto 2 again!!!!!
I even open the loom to the joining point of the coil feeds, all are soldered together thinking it may be a dry joint but all was well.
The last thing I did was to make off all 6 low tension coil connections with new crimped and soldered brass spade terminals. So far so good.............................................. ..

[j98sprint]

Welcome DAGAD,

I hope that work you did to the spade connectors solves the spark problem. There's been some talk about those connections lately. I cleaned up mine and so far (over 2 months of everyday riding) no low speed, low RPM miss.

j98sprint

Thanks for the feedback.

I'll be working my way up the harness to the igniter. I may drop the bike off the local Triumphy shop to see if they can do an electrical diagnosis and find something obvious (supposedly they can scan it via plug-in).

Thanks for the feedback.

I'll be working my way up the harness to the igniter. I may drop the bike off the local Triumphy shop to see if they can do an electrical diagnosis and find something obvious (supposedly they can scan it via plug-in).