78 CB400A low voltage

infinitiy

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Mankato, mn, usa
I am hoping someone can point me in the correct direction. Garage kept 78 CB400A and I run w/o a battery, which the cause of this is probably why I do.
Today I run w/o the battery and last fall I noticed my turn signals would only work when stopped and in gear, or throttle<25%. Headlight & marker lights work but dim when blinking. They used to work fine(with dimming) w/o the battery. Otherwise the bike runs great.
Hooked up my DMM to the source wire of the flasher and frame and got 7-8VDC at idle. Same at the battery connections. Thought maybe the rectifier was on it's way out and got a new one. That made it worse, there were no turn signals at all. I checked the three yellow wires from the Generator and DMM said 1.1ohm between each combination. I know it is supposed to be between 0.2 and 1, but that is with that particular VOM, so I figured it was ok. Out of interest I switched to VAC and on the yellow wires and got about 10VAC for each combination.
Looking at the wiring diagram there shouldn't be anything that would drop it 5V.
This is then why I run w/o a battery, It would never stay charged and throwing the trickle charger on it all the time was being hard on that old plastic cover's attachment points being on/off. Eventually the battery went bad from being so low and I never bothered to replace it.
Thoughts?
Infinity
 
Running without the battery is a sure way to burn out the charging coils. They are producing voltage when the engine is running and without a load the coils will overheat. Same goes for the voltage regulator.
At 1.1 ohms it sounds like that issue has started.
 
So the rest of the electrical system doesn't provide a sufficient load? I can see that, the system was designed to power lights etc.and charge the battery.
Ok, well then maybe I'll go pick up a battery tonight.
 
Hmmmm. The battery is still in there and negative is hooked up. The positive has been thickly wrapped with electrical tape so it doesn't touch the frame.
 
infinitiy said:
Hmmmm. The battery is still in there and negative is hooked up. The positive has been thickly wrapped with electrical tape so it doesn't touch the frame.
Click to expand...
You would have been far better off removing the negative terminal and leaving the positive connected. That way there's zero chance of shorting anything out.
 
That was a case of being lazy as the positive terminal is toward the outside of the bike and I didn't have to wrestle the battery out of the tray. But yes I agree.
 
infinitiy said:
That was a case of being lazy as the positive terminal is toward the outside of the bike and I didn't have to wrestle the battery out of the tray. But yes I agree.
Click to expand...
I do hate that battery positioning. If only they used longer cables and wires, then it could be turned around to have the negative easy and on the outside.
 
With it being a Hondamatic spare stators are rare and with that much resistance you'll need to replace or rewind it. Kirk at custom rewind in Alabama does it for about $250.

Once you get the new stator get a used regulator as you've likely stressed the old one. From here check under the rubber cover on the right side cover near the solenoid. There's a 2 pin canon plug that leads to the regulator. It's somewhat common for this plug to get corroded from an old battery. If it's corroded trim it back and recrimp with the correct tool and terminals. Vintage connections had the parts you need. Be sure to check where this wire leads at the regulator because it can travel to that side.

Once you've checked that and it's good then do a voltage drop test at the ignition switch. I would also install a quick connect to the battery for the trickle charger and just get a maintenance free gel battery otherwise pulling the battery out to top it off with distilled water will be annoying. The CBs are quite annoying with the battery tray.

Get us a picture of that positive terminal you might be able to save it with large heat shrink tubing where you double or triple it up.
 
Thanks! After some monkeying around this weekend, I learned that my DMM has a low ohm setting 0-40Ω, which I thought was just for continuity. Well when I used that, my yellow wires from the stator all were 0.8Ω (within the 0.2-1Ω spec) I did rough up the connectors with 400 grit, hit them with contact cleaner, and some dielectric grease, and the voltage at the battery terminals went up to 8.5V from the ~7V originally. I did check out the white and blue bullet connectors and they didn't have any corrosion, but I still hit with contact cleaner and the dielectric grease. I'm going to continue going through the other connectors under the side panel.
There wasn't anything wrong with the positive terminal, just wrapped the metal to stop it from touching the frame while the battery wasn't connected, thinking the dead battery was causing a voltage drop. It wasn't.
I haven't tried voltage testing anywhere else yet. It's on the list too.
 
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