Intermittent loss of power

[BA80]

I've read from the start and I'm still betting on pick-up coil wires being your problem, most likely where all the wires are held under a crimp just before they leave the case. Loosen off the crimp and start up the engine. Now pull and tug and push each wire every possible direction. This is not a "gentle" procedure - pull those wires with some attitude. If the wire is not already broken, you are not going to break it by pulling it with your fingers. If something breaks or you see the insulation stretching and necking down , you've found a problem.

+1 Absolutely.

Too many fingers in this pie. I'm backing out.

[motoman]

+1 Absolutely.

Too many fingers in this pie. I'm backing out.

Aww, come on Greg, the more ya' mix the pie fillin' the better it taste(sounds).

[CatatonicBug]

Well, I really WISH it was the pickup coil wires... That would make it easier to fix! I just took the timing cover off, removed the first clamp on the wires and re-ohm'd the connector. Absolutely no change when firmly pulling on any of the wires (tried each one, individually, from both directions). I also started the bike, and pulled on the wires while it was running, with no effect.

I ohm'd the black wire at the TCI, and got 4 ohms. Re-checked the black/white wire with ignition on, got no volts. Turn the bike on, and got .35V (yes, that's a decimal!).

I put the seat on, and ran it around the block a few times, and the cylinders never dropped out... I think I scared the problem away. I hate intermittent problems!

[dbeardslee]

Well, I really WISH it was the pickup coil wires... That would make it easier to fix! I just took the timing cover off, removed the first clamp on the wires and re-ohm'd the connector. Absolutely no change when firmly pulling on any of the wires (tried each one, individually, from both directions). I also started the bike, and pulled on the wires while it was running, with no effect.

I ohm'd the black wire at the TCI, and got 4 ohms. Re-checked the black/white wire with ignition on, got no volts. Turn the bike on, and got .35V (yes, that's a decimal!).

I put the seat on, and ran it around the block a few times, and the cylinders never dropped out... I think I scared the problem away. I hate intermittent problems!

The no resistance on the black wire means the TCI has a good ground - and 4 ohms on most dmm's is pretty darn close. Might check your grounds and see if the reading changes. The .35v on the black/white is pretty far out of spec - supposed to be 6v - and verified with the no resistance on the black wire looks like the problem may be in the TCI according to the diagnostic tests outlined in the manual. And the fact that it's been resoldered several times sorta makes it suspect.

Too bad you don't have a spare 4R0 you could swap out for test purposes. Like I said, I've got a 2H7 I'd let you try but it's not going to do you any good with the 81 ignition. I checked the manuals on the off chance that the testing procedure or voltage readings may be different for the 4R0 than the 2H7 but no joy - same procedures and readings for all years.

[bikerphil]

Don't overlook that 4 blade TCI connector, a loose connection in there won't show up on any tests. It took me months to find that weak point on my 79F.

[CatatonicBug]

So, you think I should rebuild the TCI? If the black/white wire's voltage is so far off, how it is still running?

[dbeardslee]

So, you think I should rebuild the TCI? If the black/white wire's voltage is so far off, how is it still running?

Badly, evidently. I'd be more inclined to throw myself on the mercy of the members and see if anybody had a 4R0 you could borrow before you start soldering on the TCI - particularly after what ViperRon had to say. If you put a known good unit on and still have the problem you could probably rule out the TCI as the cause. If the problem goes away with a known good TCI... that's different.

And you should probably take Phil's advice too and check that connector. Might be something easy, and personally I like to do the easy stuff first. And with the 11.2v readings at the TCI when the battery is reading 12.6v it might not be a bad idea to check all your connectors for corrosion.

But you're right about intermittent problems - I hate 'em too. Never seem to fail when you want 'em too - like trying to diagnose things. But get too far away from home and... WHAMMO.

Did you check your primary resistance readings on the coils from the TCI, and your secondary resistance readings across the coils? Might not be a bad idea to check those while you're checking stuff.

[CatatonicBug]

The connector is great. I have gone over ALL the connectors on this machine and deOxit'd them, then added a light coat of dielectric grease to each one (except the grounds, where I use anti-seize).

Not sure what you mean by primary and secondary resistance checks though.

[dbeardslee]

The connector is great. I have gone over ALL the connectors on this machine and deOxit'd them, then added a light coat of dielectric grease to each one (except the grounds, where I use anti-seize).

Not sure what you mean by primary and secondary resistance checks though.

Pull the big connector off the TCI and check the orange wire with the red/white - should be 3 ohms. Then check the grey wire with the red/white - should also be 3 ohms. That's your primary resistance check.

Then pull the plug wires and put a probe in each spark plug cap for the same coil and take a reading across the coil. Should be 15k ohms plus or minus 20%. Then repeat for the other coil. If you've got 5k resistor caps installed, then you have to bump your readings by 10k ohms - 25k ohms total. If the readings look flakey, remove the caps and measure again. Those resistor caps can wear out so that should help diagnose if you've got a bad cap. You can also test the caps themselves by putting a probe on each end and verifying that they read 5k ohms ea. That's your secondary resistance test.

If they look okay, warm the bike up and allow the coils to heat up, and check the readings again.

[CatatonicBug]

Ok, that'll have to be tomorrow's test. I don't have resistor caps. Iridium plugs have the resistors built-in.

[ViperRon]

My experience is you changer the position of the wires and it went away. TCI problems typically are solid when they come. The wire issue may not be in the flexible part even though that is the main place when you put it back make sure it does not touch the timing wheel.

[CatatonicBug]

Ok, update from a quick look this morning.

Did the primary resistance test, and for 7 ohms on both. Then, I tried to do the test on the 2&3 coil, and I had a REALLY hard time making a decent contact inside the plug caps! Mind you, these are just metal ends, crimped onto the end of the plug wires, forced into rubber 90º boots. While I wiggled around in the caps, it DID make brief contact, and gave me anywhere from 15K to 20K.

While this initially lead me to point the finger at the ends on the plug wires, I remembered that, in my previous testing, I had swapped the coils, and the problem was traced to the supply of power going TO the coils, not FROM the coils. The connectivity issues in the pug caps makes me want to re-crimp new ends on the wires just to be sure anyway though.

[dbeardslee]

Ok, update from a quick look this morning.

Did the primary resistance test, and for 7 ohms on both. Then, I tried to do the test on the 2&3 coil, and I had a REALLY hard time making a decent contact inside the plug caps! Mind you, these are just metal ends, crimped onto the end of the plug wires, forced into rubber 90º boots. While I wiggled around in the caps, it DID make brief contact, and gave me anywhere from 15K to 20K.

While this initially lead me to point the finger at the ends on the plug wires, I remembered that, in my previous testing, I had swapped the coils, and the problem was traced to the supply of power going TO the coils, not FROM the coils. The connectivity issues in the pug caps makes me want to re-crimp new ends on the wires just to be sure anyway though.

If you take your dmm and touch the probes together, what kind of a reading do you get? They're supposed to be zero resistance, but I've got one dmm that never goes all the way to zero. On that one I just take it's "zero" into account and subtract it from whatever reading I get.

20K would be out of spec, but if you're not getting a good contact the reading may not be correct. If you're using an automotive type cap you might get a better reading if you remove the little screw tips from the plugs and put them up inside the connector and make your contact with the hole in the center. Or pull the cap back a bit to expose the connector so you can hold the probe against the side of the connector. JAT

Did you get the same reading on both of them? Did you warm everything up good and try it again with the coils hot?

And just out of curiosity, are you running stock coils or something else?

[CatatonicBug]

The meter shows 0 or 1 when holding the leads together. I get that part. I didn't warm anything up this morning, just ran those quick tests before I left for work.

I'm using Accel coils, which is why the plug ends are just metal terminals crimped onto the ends of the plug wires, and why I am using iridium plugs that have the resistor built-in. The caps are just rubber boots with Harley stamped on them. They are VERY tight, so I can't peel them back at all, but I can easily see the terminals inside the boots. That's why I thought it very troublesome that I couldn't make a decent contact.

[dbeardslee]

If you're getting a reading that's 6-7 ohms (actual) that's kind of high. I'd check 'em again right at the primary leads that come off the coils and see if you get a 3 ohm reading. If you do I'd check the continuity of the orange, grey, and red/white from the primary coil connections back to the TCI. Something is adding some resistance there - either in the coil or in the wires. Pay particular attention to the red/white. It runs up through the handlebar kill switch, so motoman might have had something with his suggestion of cleaning the contacts on the kill switch.