Random Engine Failure

[ddebonis]

Hi All-

This is weird and wanted your thoughts. Over the past 800 miles (since I've had it), my bike has died while I was riding it 3 times. Each time, I was riding down the road and all of a sudden the bike was dead. I roll to a stop and then it starts right up. The bike seems sufficiently warmed up and I am not hitting a big bump or anything...

This will be tricky to solve because it happens so rarely, but where should I start.

-Danny

[Barry]

If it dies instantly without first stumbling then it has to be ignition rather than fuel.

Then if it wasn't for the fact that it starts again so quickly the usual culprit would be the electronic ignition module overheating. Might still be that so if it's the type of module where the heat sink paste can be renewed then you should do that.

[Bob_Roller]

You need to go through the electrical wiring and check the connectors for security .

I had the same problem for about 7 months, until I checked all the connectors, hasn't been back since, that was 15 years ago .

Never found anything I would consider a problem .

When you have the connectors disconnected, check the 'pins' for security, there is a small spring tab on the crimp on terminal ends, that's the only thing that prevents the 'pin' from backing out when the connectors are put back together .

Check for corrosion as well as broken or frayed wire strands where the terminal end is crimped on, wires seem to like to break at the crimp .

[montmil]

Remove the front engine cover and confirm no wires are being pinched between the internal webs of the front cover and timing chain case. Also check the connector block from the bean can harness.

The under tank ICU should have it's heat sink paste renewed. Small tube available at any Radio Shack store. Confirm the connector block at the ICU is making good contact.

The Hall sensor in the ITC "bean can" may be in a heat failure situation but I'd check all the above posted responses before cracking the can.

Inspect the ignition kill switch on the right side handlebar switch assembly. They can become problematic with age or over use.

I agree you're experiencing an ignition/electrical issue.

[steve hawkins]

Watch the rev counter next time it happens - if the needle drops instantly - it will be ignition related.

[DgM]

Coil.

[Session101]

does your gen light come on?

[79beem]

I had similar issues recently. Turned out to be a loose connector in the ignition circuit under the tank. Not obvious though. I tightly taped the connectors together with electrical tape, not pretty, but effective.

[raymr]

I second the ICU heat sink paste advice. Clean the surfaces real good and then make sure you have a nice even coating of paste, not too much, but enough to ensure full contact and no gaps.

[Barry]

The advice about not too much paste is spot on and the key to making the heat sink work properly.  Compared to metal the thermal conductivity of the paste (and that's any paste) is rubbish. It's still a whole lot better than air which is why it's used. I could dig out the figures but it's at least an order of magnitude worse than the metal of the heat sink so as Ray_MD said just enough to fill any gaps is the correct amount.

[mfrias2nd]

Sounds electrical...for sure. Can't say that's happened to me but my bike started acting up one day for no reason. I took apart all the connections and got to them with wire brushes and contact cleaner. Seemed to help a lot. Don't know exactly what was cleaned to keep it running steady but you have to think about how old these bikes are they needs some TLC.