HELP: Sudden Electrical Shutoff, then Restarts

[AnnapolisAirhead]

A riding buddy of mine has a well maintained '88 RT that he has well over 40,000 miles on and it a 'rounder. this weekend, he took a 600 mile trip through PA, checking out the leaves, etc. Its a basic bike in terms of upgrades, etc. Has a Thunderchild with a couple thousand miles on it. No driving lights, etc. He is usually the guy in front of our pack, responsible, maintains steady speeds (4200 RPM), etc. and a damned good wrench. His connections are insanely clean and he uses di-electric grease.

On his way home, the bike would cut out, power, lights, engine and all at cruising speed (60-70, even at 40mph), then will start right up again. After 20 minutes of steady riding, it'd cut out again.

My thoughts are that he should check
1.) Hall effect sensor, although I know little about them
2.) Ignition coils (dual plugged, electronic ignition)
3.) Neutral safety wire?? (guessing)
4.) Kill switcheroo dirty?

I've been searching for posts on fuses in the headlight bucket, etc. but haven't found anything similar yet.

Any thoughts on where to begin? Voltage regulator should have nothing to do with this, as IIRC it simply decides when and how much to send to the stator (yes?).

Any pointers much appreciated. He isn't much of a computer guy, so I offered to ask.

 

[bikerfish1100]

sounds most like a primary ground being interrupted. check connections at trans and battery? other locations? not likely to be an in-headlight fuse, as they only regulate auxilliary items (lights, etc)- engine operations are generally unfused.

 

[BRICKRIDER]

My late friend Joe "World Famous Tightwad" had a mid-80s R80RT that did that same thing, sorta. Turned out to be a harness connector near the frame under the gas tank that was working itself loose. I think the wires were pulled kind of tight for some reason, because it finally got solved by using a zip tie to hold the 2 pieces of connector together.

Bikerfish's comments are excellent, as usual.

Ride Safely,
BrickRider

 

[sumran]

A riding buddy of mine has a well maintained '88 RT that he has well over 40,000 miles on and it a 'rounder. this weekend, he took a 600 mile trip through PA, checking out the leaves, etc. Its a basic bike in terms of upgrades, etc. Has a Thunderchild with a couple thousand miles on it. No driving lights, etc. He is usually the guy in front of our pack, responsible, maintains steady speeds (4200 RPM), etc. and a damned good wrench. His connections are insanely clean and he uses di-electric grease.

On his way home, the bike would cut out, power, lights, engine and all at cruising speed (60-70, even at 40mph), then will start right up again. After 20 minutes of steady riding, it'd cut out again.

My thoughts are that he should check
1.) Hall effect sensor, although I know little about them
2.) Ignition coils (dual plugged, electronic ignition)
3.) Neutral safety wire?? (guessing)
4.) Kill switcheroo dirty?

I've been searching for posts on fuses in the headlight bucket, etc. but haven't found anything similar yet.

Any thoughts on where to begin? Voltage regulator should have nothing to do with this, as IIRC it simply decides when and how much to send to the stator (yes?).

Any pointers much appreciated. He isn't much of a computer guy, so I offered to ask.

How many times did this pattern repeat itself and how consistent was the time between start and cut off?

 

[kstoo]

I had a similar problem on the 1980 R100T that ended up being IN the wiring harness. Just before the wiring harness enters the headlight shell there is a crimped splice that "Y"s, splits, the wire feeding the fuses. I crimped down on that connector and have never had that failure ever again. I had to start cutting the wiring harness covering sleeve back to find this.

In other words start looking for bad connections. Even if he has 'insanely clean' connections.

Note: dielectric grease is non conductive. Electricity is not supposed to pass through it. It is an insulator. It is great to use to lubricate plastic or rubber connectors and to keep moisure out of connectors but if you get dielectric grease in the electrical connection itself you have created a bad connection. It looks clean but it is electrically dirty. It is specifically designed to keep high voltage from "leaking" from something like a spark plug cap. Use carefully and sparingly around low voltage connections.

 

[AnnapolisAirhead]

How many times did this pattern repeat itself and how consistent was the time between start and cut off?

Happened every 20-30 minutes or steady riding. He said he could basically clutch in, and hit the start button and all was fine. That was consistent (still its).

 

[AnnapolisAirhead]

I had a similar problem on the 1980 R100T that ended up being IN the wiring harness. Just before the wiring harness enters the headlight shell there is a crimped splice that "Y"s, splits, the wire feeding the fuses. I crimped down on that connector and have never had that failure ever again. I had to start cutting the wiring harness covering sleeve back to find this.

In other words start looking for bad connections. Even if he has 'insanely clean' connections.

Will pass this along to him, as I am sure he's busy checking his connections anyway.

Note: dielectric grease is non conductive. Electricity is not supposed to pass through it. It is an insulator. It is great to use to lubricate plastic or rubber connectors and to keep moisure out of connectors but if you get dielectric grease in the electrical connection itself you have created a bad connection. It looks clean but it is electrically dirty. It is specifically designed to keep high voltage from "leaking" from something like a spark plug cap. Use carefully and sparingly around low voltage connections.

Another topic debated for the ages. I have been using it on connections for cars for years. First clean the connection to keep it shiny and bright, then just a little on my fingers, all wiped off so the residual amount is all I use on the connection. He doesn't use any on the connection itself, just on the outside of them after they are connected. Any grease will insulate, but I'd not call dielectric an insulator--more of a corrosion inhibitor, not to be gobbed on. Even still, I'll pass this along to him too as any help is surely appreciated.

Thank you.

 

[AnnapolisAirhead]

sounds most like a primary ground being interrupted. check connections at trans and battery? other locations? not likely to be an in-headlight fuse, as they only regulate auxilliary items (lights, etc)- engine operations are generally unfused.

Thanks Bikerfish, passed this along to him. Stands to reason that this is a good place to look and avoid the headlight bucket if possible.

Would you agree that the voltage regulator has nothing to do with it?

 

[bikerfish1100]

does not sound like a charging issue at all.

 

[beemerguru]

Intermittant (sp) short..maybe in the wire harness to the right front under that tank..check the block connector from the right handlebar )red, black, blue, or white)

Early for it to be the can. No rain so probably not the coil...maybe the ignition control unit.

 

[ISAMEMON]

Originally Posted by kstoo
Note: dielectric grease is non conductive. Electricity is not supposed to pass through it. It is an insulator. It is great to use to lubricate plastic or rubber connectors and to keep moisure out of connectors but if you get dielectric grease in the electrical connection itself you have created a bad connection. It looks clean but it is electrically dirty. It is specifically designed to keep high voltage from "leaking" from something like a spark plug cap. Use carefully and sparingly around low voltage connections.
........................................................................................................

have not heard that before
good to know if true

 

[cjack]

Originally Posted by kstoo
Note: dielectric grease is non conductive. Electricity is not supposed to pass through it. It is an insulator. It is great to use to lubricate plastic or rubber connectors and to keep moisure out of connectors but if you get dielectric grease in the electrical connection itself you have created a bad connection. It looks clean but it is electrically dirty. It is specifically designed to keep high voltage from "leaking" from something like a spark plug cap. Use carefully and sparingly around low voltage connections.
........................................................................................................

have not heard that before
good to know if true

It's true that it is a non conductor, but it is used in connectors to lubricate and keep water out. The metal connections wipe themselves clean of it when they are plugged together.

 

[sumran]

The loose connection / bad ground / short in the harness ideas could certainly could cause his symptoms. However, it seems if that was the cause the behavior should be more erratic and would be more likely during acceleration and deceleration than at smooth cruising speed. Not trying to be disagreeable, just thinking out loud(virtually).

 

[kstoo]

It's true that it is a non conductor, but it is used in connectors to lubricate and keep water out. The metal connections wipe themselves clean of it when they are plugged together.

... most of the time ... I've had to clean up too many of these connections inherited from PO's.

 

[jforgo]

Also check

for looseness in ignition switch - intermittent connections - vibration can off/on bike. Test by tug/push on key with bike running - also slow rotation in both directions with bike running. As well as, of course, connectors on back.
I had ignition switch which was essentially disintegrating and caused these symptoms.
Also check lead from can - can be stretched pretty tight - pulling off connector, or even stretched wire disconnecting invisibly inside insulation.

 

[rpeckham136133]

I am suspecting ignition switch as well: all goes off including lights. If it were the ICU, then bike would stop running but lights should stay on?

Don't know that bike, but what about the kill switch? Sometimes, particularly if one doesn't toggle the switch frequently, they can ground out/turn off....

Any electrical switch is best excercised, but like anything, too little or too much is detrimental.. Ignition switch might be "too much", kill switch might be "too little"....

 

[AnnapolisAirhead]

I am suspecting ignition switch as well: all goes off including lights. If it were the ICU, then bike would stop running but lights should stay on?

Don't know that bike, but what about the kill switch? Sometimes, particularly if one doesn't toggle the switch frequently, they can ground out/turn off....

Any electrical switch is best excercised, but like anything, too little or too much is detrimental.. Ignition switch might be "too much", kill switch might be "too little"....

That's an interesting piece we overlooked. Thanks.

He's also looking at the starter relay as a culpit. Once started, power still runs though there??