Bike suddenly shuts off

[Llamaguy]

I went for a ride with my Church today, was going fine for about 20 miles when I went to slow down, the bike dies and won't start back up. When I got to a stop, the bike would turn over and start to fire a little, but nothing close to starting. Then after a couple of tries it stops firing all together.

So we pushed it off to the side and when on to get lost, but on the way back, we stop, it starts right up and ride for another 10 miles before it does the same thing as I come up to a stop sign. Leave it, go home get a trailer come back and it starts up, and we trailer it home.


Two things that I can think of:

1. The Ignitor box is flaking out.
2. The Fuel line is blocked, and the bowls slowly fill up while sitting, (but with the petcock closed?) and I don't think I could ride 10 miles on just the fuel in the bowls.

Anything else, is there a temp sensor that turns the bike off or anything??

[Redman]

No temperature sensor that shuts off bike. Actaully no temperature sensor of any sorts for any purpose. Although have heard of sometimes the ignition pickup or the ignition module can be temperature sensitve such that has a problem after heating up, but dont know that ignition is your problem.

Seems repeatable enought such that you can get it to fail again, and then test it by checking for spark on the plugs.

[ruddy]

Does it act like it's running out of gas? You did mention fuel blockage. It sounds like the vent in the gas tank cap is blocked. Trying it with the cap loose will tell you if that's the problem. If it is, you can clean the cap and open up the vent. It's worth a try.

[arveejay]

Did you just happen to replace the coils?

[Llamaguy]

I got it to do it twice more today, it's not getting spark on all for plugs. I swapped ignitors and that didn't help. I checked the original ignitor via resistance across the contacts like the haynes manual says, and it checked out. I checked connectivity between the ignitor and the coils and that was fine.

As far as I know, everything is original or at least replaced with original components.

The only thing I found wrong was that it was low on oil yesterday when we got it home.

[JHawkins]

I got it to do it twice more today, it's not getting spark on all for plugs. I swapped ignitors and that didn't help. I checked the original ignitor via resistance across the contacts like the haynes manual says, and it checked out. I checked connectivity between the ignitor and the coils and that was fine.

As far as I know, everything is original or at least replaced with original components.

The only thing I found wrong was that it was low on oil yesterday when we got it home.

Did you check out the fuses? Might be something weird going on down there and when it gets warm if there was some corrosion or something. That or a flakey connection somewhere on the way to the coils or pickup.

[Scud]

Check connections to your battery and fuse block. Mine had this problem and I traced it to those two.

81 GS750E

Scud

[Llamaguy]

ARGGG!!

Over a month without a problem and it did it again! It took almost an hour and a half to start. I checked all fuses, disconnected it and reconnected. wiggled everything I could then when off for a hour. I noticed it was low on oil, so I got more. I added it and then decided to remove the tank and start wiggling stuff under there and it worked.

Again, not exactly sure what I wiggled or if it was the oil, or the simple time factor.

Is there an oil sensor that will kill the engine, temp sensor or something. It dies, then won't crank over. A starter wire won't cause the dieing, and I don't know if an ignition problem will cause the no starting problem.

I don't know how to fix it if I won't know what's wrong!lohffhhafhkjhfakfalhfahflfha hf

[hungryman]

There is no fail safe device that shuts the bike down for any reason.

You are either not getting the proper air/fuel mixture or adequate spark. That's it. If it was a mechanical problem such as low compression it would run but would have no power.

[Billy Ricks]

Here are a few tests you can run to narrow things down.

This is for an '85 700 but you can probably use the same tests for your bike.

Here's how to check the ignitor. Remove spark plugs 1 & 2 and ground them to the motor so they will fire when they get power. With the ignitor facing you, the plug on the right side of the ignitor is where the signal generator plug fits. The two terminals on the right side of that portion of the ignitor will be pin 1 at the front and pin 2 at the back. The two left pins will be pin 3 in front and pin 4 at the back. Turn the ignition switch on. With a multitester set a the X1 ohm range put the + probe on pin 2 and the - probe on pin 1. Plug number 1 should fire. Next put the + probe on pin 4 and the - probe on pin 3. Plug number 2 should fire. If this happens the ignitor is good and the signal generators are suspect.


As for testing the pickups, signal generators, measure the resistance between the two wires on each pickup. You should get somewhere around 130-200 ohms. If the resistance is infinity or less than spec they are shot. You can check resistance of the signal generators by inserting the probes into the plug you removed from the ignitor. The terminals in the plug correspond with the pins on the ignitor.

To test the coils put one probe of the multitester on each of the terminals on the primary side of the coil. You should get 3-5 ohms. Check the secondary windings by placing one probe into each of the plug wires coming from one coil. Those would be 2 & 3 from one coil and 1 & 4 for the other. You should get 30-50,000 ohms for stock coils and 15-20,000 for aftermarket.

Could also be a corroded fuse block. Take it apart and inspect the innards.

[Llamaguy]

I think the last thing I wiggled before it started was actually a set of three wire connectors on the top left of the engine inside a special little boot. They were a lower gauge than most so they were probably important.

Would a bad coil really cause it not to crank over? I would understand if it just didn't have spark, but it won't even crank which is weird.

It's not the ignitor caues I've switched it out the last time it did this and it didn't help

[Dink]

You certainly have an electrical issue.
You need to resistance test wires, all sorts of wires BTW.
Best way to do it is to trace the various circuits.
From what you have said I would pay particular attention to the ignition circuit, the wiring to and from the ignition pick-ups to the ignitor, and to the coils.
Test resistance cold, then start the bike with the probes still connected to see if resistance increases.
Dink

[renobruce]

What color are the wires in that boot? Pull them apart and clean the connections. For the non-cranking issue, it might be your kill switch or starter interlock switch (for starting by pulling in the clutch) if you have one.

[Billy Ricks]

What color are the wires in that boot? Pull them apart and clean the connections. For the non-cranking issue, it might be your kill switch or starter interlock switch (for starting by pulling in the clutch) if you have one.

Sounds like the stator wires since there are three and the boot kind of clinches it. I bet they're yellow.

[Llamaguy]

I think I've got it. The stator wires didn't kill the engine or make it not start even with all disconnected...BUT there is a wire connector on the right side that comes out of the main harness that will do both.

On side has several yellow wires looping back into the connector. Does anyone know what is routed through this connection?