TOPIC:

When the points fully open should the resistance go from zero to infinite or is there still some continuity there?

The ignition coil's primary winding grounds through closed points to the engine case.

Opening of the points is the event which interrupts the ground and causes the coil to fire.

There should be no electrical continuity between the open contacts.

Good Fortune!

Then I may have found my problem.

When checking timing, I am not getting infinite resistance with the points open. Zero with them closed but when fully open the needle on the voltmeter only deflects about 1/4 over, not to infinite like I think it should. This is with me opening the points as far as they will go by hand to be sure they are not still lightly touching.

At first I thought I must be leaking thru the points plate, bad insulting washer or something touching...it happens...dealt with that before on other bikes. But its not in the plate. With the plate isolated from the bike (green/black points pulse wires unplugged from coils) I get infinite when points open.

I narrowed it down to only happening when the two red/yellow wires coming out of the coils are touching. Does not have to be plugged into the red/yellow from the bike harness, (but does it then too) but will do it if just the ends of the two red/yellow wires coming from the coils touch each other. And of course the trigger wires, green and black, have to be connected to the timing plate too.

Does the same thing happen when the ignition switch is turned OFF?

Are stock coils fitted, or perhaps Dyna coils?

If Dyna coils, would assure that a primary terminal screw head isn't shorting against the metal coil mounting spacer.

Good Fortune!

Let me try to be more clear....kinda confusing.

For this to happen. The pulse wire from both sets of points is connected to its coil, and the red/yellow wires from each coil are touching each other. (as they are when hooked into the wiring harness, they each goto the same connector)

Then I do NOT get infinite resistance with the points fully open. I get about a 1/4 deflection of the needle with the multimeter set to Rx10. I don't know if this is normal, but it tells me there is somehow some continuity coming back thru the coils?

Plus to add to the mystery....the points plate does not have to be grounded to the bike for this to happen. I can hold the points plate in my hand with one lead from the multimeter on the points leaf spring and the other lead clamped onto the points plate. Still happens.

Thinking this could be a problem in the points plate somehow. Would continuity between the pulse wires coming off the points plate would indicate a problem?




Edit : I was typing this response when you (Patton) added your response. The "let me try to be more clear" was not aimed at you. Kinda looks that way since your response is in between my to posts.

Patton wrote: Does the same thing happen when the ignition switch is turned OFF?

Are stock coils fitted, or perhaps Dyna coils?

If Dyna coils, would assure that a primary terminal screw head isn't shorting against the metal coil mounting spacer.

Good Fortune!

This is with the ignition off. Ignition system is completely stock. 1977 KZ1000 LTD.

Perhaps one of the insulating washers is defective and allowing some continuity between the spring and the mounting plate, even when the contacts are open.

While the contacts are open, there should be no continuity between the spring and the mounting plate.

Good Fortune!

For reference --




Good Fortune!

After a little more messing with it, here is what I have. Keep in mind that this testing was all done with points plate not installed on bike, just sitting to the side, not grounded to the bike thru the plate body itself.

When the points plate wiring is disconnected from the bike, it works as it should. One lead connected to one of the points spring, other lead connected to plate. Point closed = zero resistance, point open = infinite resistance.

Switch lead to spring on other set of points, same results.

Now, hookup green and black pulse wires to their respective coils, plus red/yellow wires from coils connected to the harness, or just touching = to isolate coils from rest of wiring harness = same results below happen either way.

Leads from multimeter same positions, one lead on points spring, other lead on plate. Both sets of points closed = zero resistance. Open set of points with lead connected to its spring = needle deflects about 1/4 of its range over from zero. While still holding that set of points open, open the other set of points WITHOUT the lead on its spring = resistance now goes to infinite.

Switch lead to spring on other set of points and repeat, same results.

This tells me that there is some continuity between the two coils and back to the plate. I guess the path would be, out the green wire to one coil, over to the other coil thru the red/yellow wires, back down thru the black wire and back into the plate.

Wouldn't that mean that for the coil with its points open the path to ground is never fully interrupted? Because the path to ground is still available thru the other coil and its closed points? There is some resistance there, or the multimeter would show zero, but its not fully closed either or the multimeter would show infinite.


So, if my bike was running ok I would assume this was normal. But my bike is not running normal and I am hunting the problem. I can across this while checking my points gap and timing to narrow down possible things wrong. I thought it strange that the meter needle was not fully deflecting to infinite with the points open so that's why I'm on about this.

Something else that may or may not be a clue. I decided to test voltage to the coils. Key/kill switch on for all readings. When I disconnect the coils from the red/yellow wire and just test the connector right out of the harness I show 12.5v at the battery and 12v at the red/yellow connector. Connect the coils to the harness and now I show 12v at the battery but only 8v at the red/yellow wire connector. So I drop a 1/2 volt at the battery with the coils connected, but I drop 4 volts at the coils?

Is any of this normal or do I have ignition system problems?

I now believe this is normal. Please someone correct me if I'm wrong. What I am seeing is the resistance thru the primary windings of both coils.

To check the primary windings in a coil you connect one lead to the red/yellow wire and the other to the green or black and then read the resistance. Sure enough when I check the resistance of each primary winding in each coil it is half of the reading I was seeing when checking the points.

So that's figured out. Knowing that I can reset my gap and timing and keep looking for my problem elsewhere.

While the points plate is off I'm going to pull the advancer and clean it up. Also, I have a crack in the points housing. The piece under the contact breaker cover. (the manual calls it the right engine cover) I would like to remove it and have it welded while the points plate and advancer are already out. Does the oil have to be drained to pull it off? Part #25 in this drawing.

Hmmm, 4Vdc drop, not normal....

Possibly missed it but condition of the point contacts (Pitted, carbon, melted etc...) ?

Bike running like crap (back firing, popping, won't idle etc...) ?

How old (miles) are the condensers...?

Is this occurring on both set of points/condensers...?

Possibly leaky (partially shorting to ground) condenser....

If your meter does not have capacitance measurement capabilities (condenser is a capacitor ), using resistance setting. Pop the cap leads out of circuit, connect your meter set to resistance measurement, connect your meter leads and you will see a ramping measurement as the cap charges up off the meter that will somewhat stabilize.

Leave it connected for ~ 1 minute, if it starts to fall off (decreasing resistance back to ground potential) the stabilized resistance measurement then it is Leaking charge potential...

Compare the two capacitor measurements, ~ the same...?

Or, if old, just replace for piece of mind, they're cheap insurance....

I didn't think loosing 4 volts at the coils was normal. This could still be dirty connectors causing this? But why do I get battery voltage there when coils are not hooked up and then loose 4 volts when they are? Unless the switches/connections are having trouble under load? Or more likely is bad condensers?

I think the continuity I was seeing thru the points, even with the points open, is normal now that I understand I'm reading thru the coils primary windings.

I'm not sure how old the points/condensers on the bike are. Possibly original, bike shows 11,500 miles on speedo.

Points are pitted looking, so bet some arcing is going on during opening. If need be I'll get them back on with timing/gap set and see if its sparking while running.

Overall bike runs ok....I guess. Starts right up but does pop some at idle when its cold. Cruising at steady speeds around 50-60 its great. But hard acceleration is not so great. I have eliminated the carbs and valves as being the problem so I'm looking elsewhere. I know...you'll just have to trust me on the carbs thing.

To do the test you described....lets see if I got this.

Remove the spark plug caps from either 1,4 or 2,3. Key/kill switch must be on. Set meter to resistance, one probe on one of the spark plug wires, other probe on ground? I am going to test the wire whose points are closed to see if they are charging up? Do I turn the ignition switch off to see if it leaks down? Seems with ignition on it will just keep filling the condenser back up. Then I can roll the engine over to the other set of points close and test one of its plug wires.

Plus don't open the points with the ignition on and the meter hooked up! Or boom goes the meter.

If the points/condenser are bad I think it's probably just time to put a Dyna S on there and be done with it. A new points plate is $60, so that's already half way there towards the Dyna S.