Rev counter jumping/not charging

[robtattoo]

I'm 200 miles from home, holiday Sunday, in bumfuck Kentucky.

I noticed on the ride up here, that my rev counter was bouncing & i kinda half remembered that being a symptom of something on the charging system, but I couldn't remember if I was remembering right, or my brain was just wandering.

Come to fill up with gas & no electric start. Bum. Kicked her off, ran like a champ.

Second fill up, hard to start & didn't seem to want to idle. Revs perfectly & ran fine otherwise.

30 miles down the road & I had to make a left across traffic. Pulled the clutch & she just sputtered, backfired & died.

I'm reaching back into my history here, but it's this a symptom of the rectifier having took a shit?

I'm hoping letting her cool off will get me the last 63 miles......

(Posted from the side of the road, in BFE, KY)

 

[robtattoo]

All fuses are fine, apart from the phone charger i just wired direct to the battery, yesterday.

 

[Jim]

If it's the stock rev counter, no, has nothing to do with charging. You still in the middle of nowhere?

 

[Jim]

What year bike? Stock charging system?

 

[5twins]

Well, the rectifier is a possibility, but not that common of a failure. More common is the regulator, and even more common, unfortunately, is the rotor going bad. Another possibility is worn out brushes. Once they wear too short, they no longer make good contact with the rotor. Charging drops off or even quits altogether. As you've discovered, the bike will run for a while off the charge in the battery, but once that gets too low, it quits. This is why many of us have installed a voltmeter, so we can keep an eye on the charging output. If it quits, we know and can head home, hopefully before the battery drains, lol.

 

[jpdevol]

Once running, if the headlight gets brighter with increased rpm, then you're still charging

 

[robtattoo]

If it's the stock rev counter, no, has nothing to do with charging. You still in the middle of nowhere?

Yup.
I know with the old Suzukis, if the rev counter bounced it was the reg/rec unit on its way out (I'm 99% sure anyway)

What year bike? Stock charging system?

1980, 9300 miles, yes stock system.

 

[robtattoo]

Once running, if the headlight gets brighter with increased rpm, then you're still charging

It was doing exactly that at 5:30 this morning.

 

[jpdevol]

Hopefully, it's a loose connection that can be found and tightened......

 

[Jim]

Well, if it's the charging system, your options are pretty limited out in the sticks.
The best you can hope for is someone to come along and have jumper cables, a kind heart and a little time.
Hook the jumper cables up and let the car charge your battery for 10-15 mins. That (should) put enough juice back in your battery to get you into town.

 

[robtattoo]

It's one of these, isn't it?

 

[jpdevol]

The regulator is on the other side

 

[robtattoo]

Ummmmm......

 

[robtattoo]

Hang on.
Is it that inaccessible little finned bastard?

3 white wires, 1 red, 1 green, 1 black & 1 brown?

 

[5twins]

Yep, that's your combined reg/rec unit. But like I said, that's really not at the top of the "failure" list.

 

[jetmechmarty]

Rotor is the most likely culprit. If it is bad, remove the brushes and unplug the head and tail lights. If you can get to a parts store, buy a lawn mower battery and strap it to your seat, wired in parallel with the main battery, or wire it in bypassing a dead battery. It should power the ignition for a couple hundred miles.

 

[AUTOMAN]

Phone charger on a bike?

cliff

 

[Wingedwheel]

Yup.
I know with the old Suzukis, if the rev counter bounced it was the reg/rec unit on its way out (I'm 99% sure anyway)

Might happen if the instruments were electrical but not a mechanical tach.

 

[Kevin Werner]

Rotor is the most likely culprit. If it is bad, remove the brushes and unplug the head and tail lights. If you can get to a parts store, buy a lawn mower battery and strap it to your seat, wired in parallel with the main battery, or wire it in bypassing a dead battery. It should power the ignition for a couple hundred miles.

Marty for the win!!!

 

[robtattoo]

Rotor is the most likely culprit. If it is bad, remove the brushes and unplug the head and tail lights. If you can get to a parts store, buy a lawn mower battery and strap it to your seat, wired in parallel with the main battery, or wire it in bypassing a dead battery. It should power the ignition for a couple hundred miles.

Thanks Marty!
I already disconnected the head & tail light. Didn't know about removing the brushes (which are about 1/4" before the wear line) do I literally just pull out the square carbon insert? I checked them when i hit here, but I don't honestly know what they do or how all that works.

Chris came & picked me up (which I'm NOT going to live down) & as soon as we got to his, I put the battery on charge. So far, it's charged to 13.4 & is holding. There's a drop when i turn on the ignition (is that the rotor drawing current through the brushes?) But it fired right up. Slow discharge. It's not charging at all

He's got another battery from his XS that I'm going to leave charged & I'll carry it as a spare for the ride home. I can soon switch out at the side of the road, if need be.

When i get home, I'm going to pester y'all about testing. I can do mechanics, i can do carbs & frame stuff. Tires, wheels & bearings with my eyes closed.
But the witchcraft that is electrickery never seemed to settle itself in my brain. I literally have no clue what I'm doing from here on out & nobody around me to ask.