Intermittent loss of power

[CatatonicBug]

If I pull the connector off the TCI, the bike won't run. So, this test has to be done while pressing the starter button, right? Can you tell me which wires to test together? Let's say, looking at the TCI itself, with the connector removed - Top left is 1, top right is 2, bottom left is 3, and bottom right is 4.

[dbeardslee]

If I pull the connector off the TCI, the bike won't run. So, this test has to be done while pressing the starter button, right? Can you tell me which wires to test together? Let's say, looking at the TCI itself, with the connector removed - Top left is 1, top right is 2, bottom left is 3, and bottom right is 4.

This isn't a powered test. You're just running a resistance test on the wires - no ignition. There's another test that you do for power that's done with the ignition on inserting probes from behind the connector while it's in place, but this ain't that test. I can never remember if they're paired top to bottom or side to side, but it's real easy to figure out. The correct pairing will give you a resistance reading and the wrong pairing will give you nada.

[CatatonicBug]

Ah, got it. Still, which wires are paired together in the test?

[dbeardslee]

I'll offer up a tip too. When I check pickup resistance I use a couple 1/4" spade connectors and alligator clips on my DMM. I stick the spade connectors into the connector and clip the dmm leads to the back of the spade connectors. That way I've got good connections and my hands are free to wiggle wires.

[dbeardslee]

Ah, got it. Still, which wires are paired together in the test?

Again, I don't remember which. But just try either side to side or top to bottom. You'll know when you've got the pairing right when you see the dmm jump.

[dbeardslee]

I checked the manual - it's wht/r to wht/gr and yel/gr to yel/r. And the range is 20% plus or minus.

[motoman]

Do you have that response in a file somewhere and just copy and paste it Brant?

Nope!...........but it's a common neglected issue.

[ViperRon]

Good info and all correct dbeardslee but if it measures ok cold get it warm and check again. My coil in one circuit went bad and only failed after it was hot. Soon as the bike got to temp it would be intermittent. I bypassed the coils because my cold bike check said it was ok and finally give up. Ended up taking it to a dealer and they found it. This was back in the 80's when they still knew how to work on these.

[dbeardslee]

Good info and all correct dbeardslee but if it measures ok cold get it warm and check again.

If it checks out okay cold, and both coils are close to the same resistance, they should still be close to the same resistance, albeit higher, when they're warm. So yeah, that sounds like a good idea to me.

[CatatonicBug]

Ok, if I am reading my meter correctly, I am getting 672 on one set, and 704 on the other. This is cold. 687 and 719 when hot. Of course, the dropping cylinders didn't happen while warming up before this test.

I will add that these readings are on a digital meter. I just bought a new analog meter, and it read around 850 on both when cold, then 750 and 800 when hot. Not sure why, maybe it's just the analog-ness of the meter, and the small dial on it.

[dbeardslee]

Did you wiggle the pickup coil wires around and check for fluctuations in resistance while you were testing?

Might not be a bad idea to check your voltages at the tci too. With the connectors in place and the ignition on check grey to ground (12v), white/red to ground (12v), black/white to ground (6v), orange to ground (12v) and red/white to ground (12v). You can stick one probe in from the back of the connector to make contact at the connector, and just touch the other connector to the frame in a spot where you can get a good contact.

[motoman]

Yes, it seems to start fine when cold, and the problem doesn't start up until the engine warms up. I have not ohmed anything.

Start with an OHM ckeck of the coils..........when disconeccted and warmed up real good with a heated dryer or hair dryer..........may surprise you the tenths of OHM loss doing this. Using both hands, stretch each of the wires every inch(ones under the ignition cover}.

[CatatonicBug]

Did you wiggle the pickup coil wires around and check for fluctuations in resistance while you were testing?

Might not be a bad idea to check your voltages at the tci too. With the connectors in place and the ignition on check grey to ground (12v), white/red to ground (12v), black/white to ground (6v), orange to ground (12v) and red/white to ground (12v). You can stick one probe in from the back of the connector to make contact at the connector, and just touch the other connector to the frame in a spot where you can get a good contact.

No, I didn't do any wiggling. Didn't know I was supposed to.

Checked voltage (had to turn ON the kill switch too), and got 11.2V on gray, orange and red/white. Black/white had no voltage.

[dbeardslee]

No, I didn't do any wiggling. Didn't know I was supposed to.

Checked voltage (had to turn ON the kill switch too), and got 11.2V on gray, orange and red/white. Black/white had no voltage.

Gotta do the wiggling. Pulling on them like motoman suggested is a good idea. You're looking for breaks or bad connections in the wires.

11.2v at the TCI is generally an indication of corroded connectors assuming you've got over 12v at the battery. No power on the black/white isn't good. You sure you had good contact from the back of the connector and a good ground on the frame?

[CatatonicBug]

I'll do the wiggling tomorrow. I have 12.6V at the battery. I was touching the negative terminal on the battery. Definitely had decent contact at both points. I'll double check tomorrow though.