My first electrical puzzle

[Norton7d]

Here is the chain of events;

Waking a 76 with 9k miles from approximately 3 years of sleep.
Clean carbs, oil change, new battery, it fires up yesterday with only a quick blast of starting fluid, runs fair considering the amount of vacuum leaks I identify. Repeated starts with E start all go successfully.
Today I'm back in garage to work on vacuum leaks, turn on key, neutral light is on but no action when starter button is pressed or horn, I kick it twice on choke and it fires right up.
Run for a while then shut it off, turn key back on, horn and starter work. Do this a couple more times while working on other issues, each time successful Estart, then it does it again, no horn no starter but the lights work if tested....so what is this?
Need to clean connections on back of ignition switch?
Need to clean connections in headlight bucket?
Connections inside handlebar switches?
Or check other components I haven't mentioned?
Once again, the lights work when the starter & horn don't.

Thanks

 

[member28833]

Hello puzzled. You are describing some common symptoms. Having experienced similar symptoms let me suggest a few quick checks.
Firstly , of course charge and confirm your battery is charged , approximately 13 + volts.
Now remember the starters are notoriously weak. I actually prefer to kick start these for diagnosing.
Now once it is running are you able to confirm that the bike is charging it’s own battery? Measure voltage at the battery posts, easy.
Sometimes you can very easily improve the bikes charging performance by simply cleaning the two slip rings on the rotor under the left side timing cover. Those carbon “brushes” haven’t been cleaned for a long time it seems on your own bike.
Electrical cleaner on clean cloth rag might just be enough to get some measured charging out of that rotor/stator, 13.5 + above say 2500 rpm ?
if that doesn’t quickly help you evaluate your charging system,
Your going to get reading threads !
Good luck ! Kick it !
-RT

 

[Jim]

Need to clean connections in headlight bucket?
Connections inside handlebar switches?

Yes and yes...... The ground path on these bikes is an odd one. There's a ground (black) wire in the headlight bucket. It goes to the left handlebar light switch. From there, the switch is grounded to the handlebars. Ground... then travels through the handlebars... to the right switch. When you press the starter, it grounds the solenoid through this path to the headlight bucket, eventually finding its way to the frame where the batt. is grounded. Horn follows the same path. If you lose the ground at the left switch... or the bucket, you'll lose both the starter and the horn... and only those two systems... and that is your problem, right?

 

[Norton7d]

Yes and yes...... The ground path on these bikes is an odd one. There's a ground (black) wire in the headlight bucket. It goes to the left handlebar light switch. From there, the switch is grounded to the handlebars. Ground... then travels through the handlebars... to the right switch. When you press the starter, it grounds the solenoid through this path to the headlight bucket, eventually finding its way to the frame where the batt. is grounded. Horn follows the same path. If you lose the ground at the left switch... or the bucket, you'll lose both the starter and the horn... and only those two systems... and that is your problem, right?

Yep, that is the problem, looking back after listening to myself read your tip, i should have juat tried to ground the horn, cause if it had power which now i assume it did, just ground the other post and that would prove it was a grounding issue, the tank is off so it is right there for me to test...duh!

 

[Norton7d]

Hello puzzled. You are describing some common symptoms. Having experienced similar symptoms let me suggest a few quick checks.
Firstly , of course charge and confirm your battery is charged , approximately 13 + volts.
Now remember the starters are notoriously weak. I actually prefer to kick start these for diagnosing.
Now once it is running are you able to confirm that the bike is charging it’s own battery? Measure voltage at the battery posts, easy.
Sometimes you can very easily improve the bikes charging performance by simply cleaning the two slip rings on the rotor under the left side timing cover. Those carbon “brushes” haven’t been cleaned for a long time it seems on your own bike.
Electrical cleaner on clean cloth rag might just be enough to get some measured charging out of that rotor/stator, 13.5 + above say 2500 rpm ?
if that doesn’t quickly help you evaluate your charging system,
Your going to get reading threads !
Good luck ! Kick it !
-RT

I will do this also, even thiugh i dont think its a charging issue, yet anways.

 

[Norton7d]

Yes and yes...... The ground path on these bikes is an odd one. There's a ground (black) wire in the headlight bucket. It goes to the left handlebar light switch. From there, the switch is grounded to the handlebars. Ground... then travels through the handlebars... to the right switch. When you press the starter, it grounds the solenoid through this path to the headlight bucket, eventually finding its way to the frame where the batt. is grounded. Horn follows the same path. If you lose the ground at the left switch... or the bucket, you'll lose both the starter and the horn... and only those two systems... and that is your problem, right?

Jim, I just looked at the area behind my headlight bucket. There is a short blackwire with a ring, ready to be grounded by a bolt / frame attachment point but, it's not hooked up to anything. Where does it get attached?
Also, even with it disconnected, the horn worked on this attempt, so apparently this grounding component is not necessary for all electrical issues to occur properly.

 

[Jim]

I just looked at the area behind my headlight bucket. There is a short blackwire with a ring, ready to be grounded by a bolt / frame attachment point but, it's not hooked up to anything. Where does it get attached?

Can you give us a pic of it?

 

[gggGary]

Pobably one of two, front turnsignal grounds.

 

[Norton7d]

Pobably one of two, front turnsignal grounds.

Currently, factory turn signals are not on the bike, but this wire length seems like it might want to ground on a turn signal attachment point.
haven't looked inside headlight bucket yet, but I assume this comes from one of the many harness junctions.

 

[Jim]

Yeah... looks like a signal ground. If you're not running t-signals you could just stow it or remove it.

 

[Gator xs2]

I’m in the hurt locker with my XS2 wiring also. No horn, decomp/Start switch and blowing fuses with right side flashers on. Go figure. Had to walk away for a few days. Unplugged everything and will start over. Bob sent me a great diagram but still not completely accurate.

 

[5twins]

When you get one of these, you need to go through all the wiring. Clean it, check all the connections, clean all the connections, and repair any rubbed bare wires you find, and you usually do find a few. If you don't do this, you'll be plagued with phantom electrical problems like you're experiencing now on a fairly regular basis. I start back at the tail light and work my way up to the front, finishing at the headlight bucket. Handlebar controls and ignition switch get cleaned out too.

You seem to be suffering from an intermittent ground loss for your handlebar control assemblies. As mentioned, they share their ground through the handlebars. Later models have a ground wire in the left control running into the headlight. Earlier models sometimes have a ground wire connected to one of the handlebar clamps instead. There doesn't seem to be a wiring diagram for your '76 model and the earlier ones don't show much. So, it's difficult to say which way your handlebars get their ground. You could look for a ground wire in the left control. It would be a black wire attached to one of the screws in the housing, effectively grounding the whole housing .....

The black wire runs into the headlight and connects to one of the ground wires coming out of the harness. The harness ground wires run back and ground to the frame. Trying to ground to the headlight bucket or fork isn't good enough. It would be unreliable because of it having to pass through the greased steering bearings to get to the frame. This could be your issue.