CM185T sudden electrical failure

[current resident]

I decided to take the bike on a trip. ~280 miles was the planned route and all was well (beside exhaust bolt falling off). There was a stretch between two cities that was 20-30 miles, (I had been running nearly nonstop for the past 100 miles or so) so I decided to stop for a single minute, then I continued.

At the next city, I approached the first stoplight, I pulled the clutch in, and nothing. All the lights go out, the engine stops completely, everything is gone. This was after a total of 238 miles of riding that day.

The bike was towed at midnight, and back at home now trying to figure out what could've failed or shorted. I couldn't see any bare wire on the harness on the frame, I checked behind the headlight, I switched the battery out, charged it, fuse is fine. The best I've gotten is the rear parking light setting on ignition turning the taillight on. I hate electrical and I don't know what I'm doing

 

[stl360+450]

Sounds like it could be related to the main [key] switch. On the older models that I know better, the main switch brings power (red) to the rest of the harness (black). Probably similar on yours and the other observations you made rule out some other possibilities.

I had to have a bike towed last year for a similar reason and it was the battery ground cable that failed. I couldn't find it in the side is the road, but once home it took five minutes to isolate.

 

[current resident]

Sounds like it could be related to the main [key] switch. On the older models that I know better, the main switch brings power (red) to the rest of the harness (black). Probably similar on yours and the other observations you made rule out some other possibilities.

I had to have a bike towed last year for a similar reason and it was the battery ground cable that failed. I couldn't find it in the side is the road, but once home it took five minutes to isolate.

I took a look at these items. I replaced the OEM switch with an extra I had, nothing. The battery does have ground and things ARE receiving power, allegedly but just doesn't seem like a lot. Maybe I need to focus on the battery again

 

[ancientdad]

Maybe I need to focus on the battery again

If you charge the battery, then let it rest for at least a half hour and it reads less than 12.6v, it's bad or going bad. Also, what amperage output charger are you using? These small batteries shouldn't be charged at any higher than 0.5 amp to 1 amp level or they can be damaged permanently. If your charger is 1 amp or higher output, it should only be charged for a short period of time and definitely not overnight.

 

[stl360+450]

Maybe there is a broken wire or a place where the the harness has rubbed on some part of the bike. I would be looking heavily at the battery cables and following power around the harness to isolate.

 

[ericfreeman]

I've had 2 batteries fail internally and they did just what you experienced: good one minute, dead the next.

 

[current resident]

If you charge the battery, then let it rest for at least a half hour and it reads less than 12.6v, it's bad or going bad. Also, what amperage output charger are you using? These small batteries shouldn't be charged at any higher than 0.5 amp to 1 amp level or they can be damaged permanently. If your charger is 1 amp or higher output, it should only be charged for a short period of time and definitely not overnight.

I believe my charger is .5 amps, 6 volt system too. I have 3 batteries total, which all may be bad or good to try.

 

[ancientdad]

I believe my charger is .5 amps, 6 volt system too.

Good, and my duh for not remembering it's 6v. Your half amp charger is still a bit strong to leave on that battery for very long.

I have 3 batteries total, which all may be bad or good to try.

You know what they say in the NFL, if you have 3 quarterbacks you have none.

 

[current resident]

Good, and my duh for not remembering it's 6v. Your half amp charger is still a bit strong to leave on that battery for very long.

You know what they say in the NFL, if you have 3 quarterbacks you have none.

I took a look at it and none of my batteries have a voltage above.... 5 volts, according to my analogue multimeter (lost my digital one) including the ones I had plugged into that .5 amp charger.

 

[current resident]

If you charge the battery, then let it rest for at least a half hour and it reads less than 12.6v, it's bad or going bad. Also, what amperage output charger are you using? These small batteries shouldn't be charged at any higher than 0.5 amp to 1 amp level or they can be damaged permanently. If your charger is 1 amp or higher output, it should only be charged for a short period of time and definitely not overnight.

Took another look, the supposed failed battery reads ~6.1v. im gonna check up on the harness. I saw no visible damage, and I feel it any damage were present it would be at the headlight housing entrance or the frame near the engine

 

[current resident]

If it really gets desperate, I have a bunch of cm200 parts, including the harness

 

[stl360+450]

Took another look, the supposed failed battery reads ~6.1v. im gonna check up on the harness. I saw no visible damage, and I feel it any damage were present it would be at the headlight housing entrance or the frame near the engine

I wouldn't rule anything out in terms of possible locations for harness wear, but the fact that the power loss was sudden and total would suggest a break in a critical spot.

Analog meters are cool, but a cheap digital replacement might be handy until you find your other digital one.