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Another no electrical power issue...

esh21167

esh21167

Veteran Member
Joined
Apr 10, 2021
Total Posts
508
Total likes
249
Location
Reading, Pennsylvania, US
'79 CM400T (manual). Riding along and suddenly no electrical power. Battery is reading 13.3v. Continuity checked out on all three glass fuses, cleaned connections there also. Checked wiring connections in headlight bucket, and all are secure. The individual grounds (in the 4 part connection) are all 13.3v to battery positive terminal). There is this seemingly 'extra' connector, but no other wires that can be connected to it. That also tests 13.3v to the battery. I had this apart last year and don't even remember that extra plug, but that doesn't mean anything, lol.

Anything else to check as far as grounds?

Potentially ignition switch?
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"Suddenly" lost power sounds like a wire or a wire connection, holding on by a thread, suddenly breaks.
Could be:
A wire inside of a plug has disconnected. I've had that happen. Boom, no power.
A ground wire breaks from its mount, or the ground wire finally corrodes completely.
A fuse you may not have found finally goes. I've had that happen as well.
A connector plug thought to be tight, isn't.
Does the empty green connector have power? If the empty green connector, was empty while riding, then maybe no issue. I would look for an empty male connector of the same color.
The battery has shorted out. Not sure if a bad battery shows voltage. But IF the battery went bad, one would suspect energy drain before system fail. (IMO)
 
Spokes said:
"Suddenly" lost power sounds like a wire or a wire connection, holding on by a thread, suddenly breaks.
Could be:
A wire inside of a plug has disconnected. I've had that happen. Boom, no power.
A ground wire breaks from its mount, or the ground wire finally corrodes completely.
A fuse you may not have found finally goes. I've had that happen as well.
A connector plug thought to be tight, isn't.
Does the empty green connector have power? If the empty green connector, was empty while riding, then maybe no issue. I would look for an empty male connector of the same color.
The battery has shorted out. Not sure if a bad battery shows voltage. But IF the battery went bad, one would suspect energy drain before system fail. (IMO)
Click to expand...

I had this issue a couple years ago and it was just a loose ground connector, but I'll triple check all the connectors.

Are there any other fuses other than the three under the side panel?

When you ask 'does the empty green connector have power?' I'm not sure how to check that. I put the one probe of the meter on it and the other probe on the positive battery terminal and it showed 13.3v. But again, I see no mating plugs for that.
 
esh21167 said:
When you ask 'does the empty green connector have power?' I'm not sure how to check that. I put the one probe of the meter on it and the other probe on the positive battery terminal and it showed 13.3v. But again, I see no mating plugs for that.
Click to expand...
To check power in any wire, whether that wire is supposed to have power or not, you'd hook the test light to ground and use the probe to see if any power exists.
 
verify power going through the RED two wire connector on right hand side (battery side) that connects to wiring harness, I don't see anyone mention that and it is high failure point, there are two wires in there and if only one of them breaks then its hard to tell its broken without testing with meter.

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Your horn isn’t working either. That’s the green tube connector that for some reason connects to a black wire to the horn. Technically “light green” but after 45 years not so light anymore. Why they didn’t just pick another color I don’t know. It’s confusing as heck when you feel like you’re plugging a hot straight to a ground.

I’m voting ignition switch as well. They get touchy and will do everything that you’re describing.
 
Yes could be ignition switch in diagram below with keyswitch on if you have power on the red wire but not on the black wire at the 6 pin connector in the headlight bucket, then look at the ignition/key switch.

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Having recently been over almost every inch of my wiring (same bike), I was not impressed by the single grounding (to frame) eyelet under the tank at or near the CDI box mount. There was an unused female green (formerly for a 3 wire winker relay) that I used to run an extra ground under the airbox and directly to the battery negative. Ahhhh, peace of mind.

EDIT: Not the same bike but similar.
 
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All power for the bike comes from the solid Red wire at the battery, the Red w/White is the charging side coming from the regulator.
Power from the battery goes thru the 15A fuse next, top one in the box.
From the fuse box power goes to the Ign switch for distribution to Black, Brown and Brown w/White.
Unplug the 2 wire connector(Red wires) at the solenoid and verify battery voltage. Good?
Next use a VOM to check input and output using the brass clips, not the fuse ends. Good?
Check for battery power on the Red wire going into the ignition switch.
 
At the cost of being deemed mad and possible accusations of lunacy (humor). Check the taillight filament.
My 1968 Harley Rapido 125 had the same issue. Cruising along, stall! No spark! At 16 I lost my mind! Went over every inch of the bike. The bike was new!

My brother returns from Viet Nam. He says: Chip, your taillight bulb filament is broken. Put in a new bulb and your bike will start! I verbally abused him, questioned his sanity. I replaced the bulb. The bike started. Ate a crow dinner with extra helpings.

For kicks and grins, replace the taillight bulb.
 
Spokes said:
At the cost of being deemed mad and possible accusations of lunacy (humor). Check the taillight filament.
My 1968 Harley Rapido 125 had the same issue. Cruising along, stall! No spark! At 16 I lost my mind! Went over every inch of the bike. The bike was new!

My brother returns from Viet Nam. He says: Chip, your taillight bulb filament is broken. Put in a new bulb and your bike will start! I verbally abused him, questioned his sanity. I replaced the bulb. The bike started. Ate a crow dinner with extra helpings.

For kicks and grins, replace the taillight bulb.
Click to expand...
I’ve had the same with a horn. Somehow the entire switched circuit routed through that and when it went bad it was a ridiculous gremlin to chase down. I think that’s why Honda started doing a separate circuit for just the taillight.
 
Me too, with a headlight glass globe popped out of it's brass base.
You'd think it would blow the 15 amp glass fuse.

Speaking of glass fuses, they can be deceptive too. Look good but not.
 
Thanks everyone for the input. I found the issue. And as you age, you forget that you had the same problem in the past...

Wire connection broken from ignition switch. Hopefully my soldering job will hold this time. I took more effort to really clean the contact area.

Working now. I will definitely bookmark this thread though for the future.

Switch1.jpg

Switch2.jpg
 
esh21167 said:
Thanks everyone for the input. I found the issue. And as you age, you forget that you had the same problem in the past...

Wire connection broken from ignition switch. Hopefully my soldering job will hold this time. I took more effort to really clean the contact area.

Working now. I will definitely bookmark this thread though for the future.
Click to expand...
Well, I was close.... glad you found it.
 
esh21167 said:
I'd say you were 99% right! Just not the switch itself.
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It's the internal contacts so often that's the first thing I suspected. But, I did that with my old dryer, wasted money on an unnecessary part and then gave it away because I went with the first thing I suspected... :rolleyes:
 
Well apparently my soldering skills are still terrible. Took the bike on an overnight and about 80 miles from home today, my wife (leading) pulls over and tells me I have no headlight... Same connection came loose.

At least it was a daylight trip home. IDK, I used flux core silver solder. Held the iron in the connector, put the wire in the connector, touched solder to the wire and it appeared to flow around pretty well.

Maybe I'll run a small sheet metal screw in there, lol. (No, I won't do that.)
 
EzPete said:
Your horn isn’t working either. That’s the green tube connector that for some reason connects to a black wire to the horn. Technically “light green” but after 45 years not so light anymore. Why they didn’t just pick another color I don’t know. It’s confusing as heck when you feel like you’re plugging a hot straight to a ground.

I’m voting ignition switch as well. They get touchy and will do everything that you’re describing.
Click to expand...
Open up the Ign. switch at the base,the contacts.
I like to have a spare ign. switch with good parts (y)
 
Time to get a new ignition switch. I started having the same issues with my CB360t. I bought the whole key/lock kit. Ignition switch, tumbler for steering lock and seat lock. SO 1 key, and the switch is new. MY old ignition switch, despite taking apart, cleaning, kept deteriorating. The plastic, phenolic bits all get old and brittle. Save the grief.
 
So, saga changes. All was well for a couple days. Now, when attempting to start over the last few days, I get a few turns of the tarter, then nothing. Now, all I hear is a single click of a relay (?) near the battery and no starter action. When I push the start button, all other lights go out until button is released. Battery always showing 95% +, all lights, horn, etc. working.

Starter going? Any methods/hints on encouraging it?
 
esh21167 said:
So, saga changes. All was well for a couple days. Now, when attempting to start over the last few days, I get a few turns of the tarter, then nothing. Now, all I hear is a single click of a relay (?) near the battery and no starter action. When I push the start button, all other lights go out until button is released. Battery always showing 95% +, all lights, horn, etc. working.

Starter going? Any methods/hints on encouraging it?
Click to expand...
Could be the starter, but it could also be the solenoid (some call them starter relays). To test the starter, take a wrench or screwdriver you don't care about (it will get small burned spots on it from the amperage involved) and jump across the heavy terminals on the solenoid to mimic the connective action of the solenoid. If the starter is good, and my guess is probably so, then it will turn normally when the solenoid is jumped/bypassed. The lights are supposed to turn off during cranking to divert all electrical power to the starter.
 
ancientdad said:
Could be the starter, but it could also be the solenoid (some call them starter relays). To test the starter, take a wrench or screwdriver you don't care about (it will get small burned spots on it from the amperage involved) and jump across the heavy terminals on the solenoid to mimic the connective action of the solenoid. If the starter is good, and my guess is probably so, then it will turn normally when the solenoid is jumped/bypassed. The lights are supposed to turn off during cranking to divert all electrical power to the starter.
Click to expand...

As I read your reply, that's what I need to do sometimes with my tractor as it is a bit ornery at times.

That did not turn the starter. (Small sparking did show connectivity.) Did same with my CB400A and it worked immediately. So likely the actual starter motor?
 
esh21167 said:
As I read your reply, that's what I need to do sometimes with my tractor as it is a bit ornery at times.

That did not turn the starter. (Small sparking did show connectivity.) Did same with my CB400A and it worked immediately. So likely the actual starter motor?
Click to expand...
OR the battery, since you mention the small sparks when you jump the solenoid terminals. It's should spark strongly enough to cause small burned spots on the wrench or screwdriver, so check the battery voltage as it is right now at rest. Below 12.6 is no good.
 
I guess 'small' is relative.

Battery is about 1.5 years old and good voltage at 12.9. However, what the heck causes this kind of case deformation? I guess that's what I get for buying a cheap Chinese battery. Not feeling great about that. It does have a 'softer' plastic case, not high impact like the Mighty Max I got for my 400A.

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That reminds me of a battery that has suffered excess voltage during charging, it can generate too much internal heat and expand/warp the sealed case. It might show 12.9v, but seeing it would cause me to want it load-tested to see if that's not just a surface voltage reading.
 
You were right (again)!

That battery is bad. Swapped batteries.

The known good one from the 400A shows 12.9 at rest and easily started the 400T with voltage only dropping to like 11.6 during starting. The suspect battery suddenly only read 11.8 at rest, would not start the 400A, with voltage dropping to 7.8 during attempted start.

Now the question of what caused that battery damage. You said it looked like overcharging. I had both bikes on the same 4 port tender through the winter. I did not notice that deformation in the spring nor after two days of riding in hot weather when the wire broke off the ignition switch, so hopefully nothing with the bike charging system. Only noticed it today after sitting a few days and no start condition. It was on the tender though. Is it possible something started and the tender exacerbated a problem? Or if there was an overcharging problem, would the degradation continue after that event?

Regardless, a new battery is in order, but want to prevent the same issue.
 
Personally, I've thought many times about buying a tender, but then I hear stories of others who are using them and finding out the batteries went bad despite the tender saying they were good so I've never felt they could be trusted to leave on batteries constantly. Obviously I don't know the reason, but if you buy a quality AGM it should last at least 5 years and they can sit for months at a time without a charge and still be at about 90% status. I bought this charger for my 2 lithium ion/lifepo batteries and it works just as well on an AGM, but I don't leave it on them all the time. The lithium ion in my red 450 is now 7 years old and it's still just fine, but it isn't exposed to continuous charge like a tender would do. And the AGM in my 900 is about 4 years old and sits for months between maintenance charges and it's always within 90% to 95% when I connect it up.
 
Yeah. Those tenders aren’t great. Particularly if they sit in there for a long time.
The low and constant load like burned some cells out, when you would ride it, the battery no longer had the capacity to take the full charging input from the bike and cooled them even more.

If you’re going to run a tender, put it on a timer.
 
I have also read mixed reviews about tending for long periods. The unit I have (https://www.batterytender.com/products/four-bank) is supposed to be 'sensing' to when voltage is in a certain range, it goes to 'float' to prevent overcharging. I can only speak for my situation, but three other bikes were on that same tender (it's a 4 battery model) and no issues. So I suspect the cheap $20 Chinesium battery may have been the weak link.

The timer seems a good idea as well.
 
One way to be safe with a battery tender, long term, is to plug it into an outlet-mounted electrical timer. You can set to come on for 10 minutes a day, or any other time interval you want.
 
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