Ignition problem; Motor starts and runs - but dies!...

[JannPedersen]

My '95 V-Max has before the following description been running absolutely perfect, with full power and no issues regarding nor cold or hot start.

Last year before winter I had on the latest 3 rides the following experience - every time:

Motor starting perfect, after a bit of warming up I drove off and after approx a mile or so with easy-going driving the motor died completely - as if I had turned the ignition key to off! No previous warning as with strange sounds or behaviour or other signs showing that something was wrong. No burned fuses.
After approx 10 minutes (or the time it takes to smoke a cigarette) I could crank up the motor and drive off again. After this there was no disruption and it ran like a dream for hours with the usual full power. Even after short stops it started and ran perfect.

This year as I went for the first ride the fault came again. But this time it did NOT start after 10 minutes. After approx 1/2 hour it just barely started, I could only just keep the motor running and it had almost no power! Since it had started raining (typically my luck), I instantly drove off heading home, but after 1/2 mile it just died again. 15 minutes later I could start it and I drove off the last bit where it again died just in front of my driveway.

Well into my garage I began to disassemble it with my suspicion on faulty ignition coils. Off with the coils and measure the resistance in them. Both primary and secondary values are ok according to my Haynes Manual. Measuring cables and plugs also seems ok. Battery is almost new and has lots of power. The wiring seems visually ok.

What can be the cause of this problem?

Input and suggestions will be much appreciated.

 

[Fire-medic]

I suspect your pick-up coil. It heats up, and goes 'open,' (open circuit) and dies. When it cools-down, the circuit closes (continuity restored) and it runs again. The OEM pick-up coils aren't cheap. There are aftermarket ones, and those with 1985-'89 have two coils/5 wires. The 1990-'07 are two wires.

 

[JannPedersen]

I suspect your pick-up coil. It heats up, and goes 'open,' (open circuit) and dies. When it cools-down, the circuit closes (continuity restored) and it runs again. The OEM pick-up coils aren't cheap. There are aftermarket ones, and those with 1985-'89 have two coils/5 wires. The 1990-'07 are two wires.

Thanks for your reply - which seems like a likely reason for my ignition troubles. Aren't there ways of simulating/provoking the error, so that I don't have to change components based only on the suspicion?

 

[Radioguylogs]

Connect an ohmmeter to the coil(s) and heat it gently with a heat gun or hairdryer?

 

[Fire-medic]

Impedance test, pick-up coil
Should read
94-127 ohms

 

[JannPedersen]

Hi guys,

Today's update:

I had the entire bike reassembled today, and would make at test-start: It started and ran perfekt.
After approx 10 minutes i saw the temperature gauge move a little bit. It was now time for a litte revs - and suddenly it died completely!
I had it at about 5-6000 revs when it happened. I noticed that the rev-counter died and vent to 0 instantly as if the power to it had been cut, long before the motor had lost its revs and came to a completely stop.
After the annoying silence I heard 3 or 4 clicking sounds as if a relay was working on and off and after that, completely silence!

A few minutes ago I tried starting it again after 5 hours of cooling off. It started and ran just as perfekt as always.

A few thoughts: IF the culprit here is my pickup-coils, would the rev-counter come to a stop the way it does? Wouldn't it decrease the movement of the needle compared to the motors actual rpms?

And wouldn't the oilpressure lamp turn on when the motor (still with ignition on) came to a complete stop?

 

[one2dmax]

If the power is cut to the coils it will immediately cut the tach to zero (or at least as fast as the needle can fall). It is not tied to the engines revs. Also, the light (on a gen 1) is a level light and not a pressure light.

 

[JannPedersen]

If the power is cut to the coils it will immediately cut the tach to zero (or at least as fast as the needle can fall). It is not tied to the engines revs. Also, the light (on a gen 1) is a level light and not a pressure light.

You are absolutely right regarding the oil level lamp. I remembered it wrong.
It turns on briefly during cranking the motor, and turns off the same moment the motor starts.

Today I tried starting it again. Same positive willingness as usual. This time I let it idle (high, about 2000 rpm), without revving it further. About 6 minutes later it died spontaneously. This time without the clicking sounds.
I suspect that what I heard yesterday maybe was the fuelpump giving a few clicks?

After a short while I tried again. This time it fired once and then no sign of life. 2 more times it gave same result.

 

[one2dmax]

On the oil light. During cranking it and the low fuel bulb both are turned on as a test of the bulbs. Thanks to the two position start button (which also kills power to the headlights when the start button is pushed in).

 

[JannPedersen]

Impedance test, pick-up coil
Should read
94-127 ohms

View attachment 88523

Impedance test, pick-up coil
Should read
94-127 ohms

View attachment 88523

Is this the part you are referring to?

 

[Fire-medic]

Yes one on 1990-2007, and two on 1985-1989.

 

[JannPedersen]

Yes one on 1990-2007, and two on 1985-1989.

Mine is a '95; with two wires coming from it.
So it's just about measuring resistance between the two wires during heating up the coil with a heatgun?
I did the same with the stator coils, heating it up to about 90 degrees Celsius - with no change in resistance.

 

[Fire-medic]

Yes you can try that.

 

[JannPedersen]

Yes you can try that.

You think this might indicate that the pickup coil is FUBAR?

 

[JannPedersen]

...And when heating the coil just a little bit...

 

[Fire-medic]

Going 'open' when it's heated would indicate a bad pickup coil.

 

[Radioguylogs]

I think you found a smoking gun.

 

[JannPedersen]

Today I received the package with the new OEM pick-up coil...but: When I connect the multimeter it measures a resistance of 255,6 Ohm!
Is that a problem???

 

[Fire-medic]

Try reading the circuit from the other end.

 

[JannPedersen]

Try reading the circuit from the other end.

"From the other end"?
IMO a coil resistance would be the same no matter which way around you measure it.
Do you mean at the end of the wires? The reading here shows approx 0,4 Ohms more than measured directly on the pick-up coil.
I´m not sure I quite understand what you mean - please help me...