11 replies to this topic

[Bugtarget]

Hi All,
Just after leaving home today the charging light came on. It was intermittent and inconsistent but oddly enough was often going off when the rev's were low and staying on when high. I headed home and put a voltmeter to the battery without the bike running and got 12.85. Started the bike and the reading was jumping around in the low to mid 12 volt area. Even at high rev's, 5K+, it never got higher than the static battery reading of 12.85. Shut the bike down when I started smelling that dreaded electrical hot/burning smell. Checked the ground wires from the regulator and found them all in good shape. The previous owner was great about grounding and sorting this bike out. It looks to have three grounds for the regulator. In looking around and checking I did find that one of the two bolts that hold the starter in place was completely loose/out. The other bolt was holding it on but it was a touch loose also. Don't know if this is related or not. After checking the grounds and tightening the starter bolts I started her up again. The reading was a steady 12.21 no matter the rev's. Got the smell again and shut her off. Maybe 60-90 seconds or so was all I had it running but the regulator had gotten too hot to keep a finger on. Checked the fuses and the #3 30 amp "battery recharging" fuse was blown. What would be the next steps in tracking this problem down?
Thanks!

A fresh regulator was all that was needed! Sorry for all the drama from the electrically challenged!

[thumper]

When running above 3000 rpm you need 14.2 volts.
If it were me I would buy 2 fuses replace the bad one and check the voltage.
Get ready to replace the voltage regulator!!
Use the second fuse after the regulator has been replaced.

[Bugtarget]

When running above 3000 rpm you need 14.2 volts.
If it were me I would buy 2 fuses replace the bad one and check the voltage.
Get ready to replace the voltage regulator!!
Use the second fuse after the regulator has been replaced.

Update-Got a pack of 30 amp fuses. Put one in and it immediately blew. Bike was not running and the key was in the off position. I'm electrically challenged. I have another regulator, a used one, but don't want to hook that up and blow it. I suppose that everything else in the system could be okay and it's just that the regulator went south. What to do next? Install the working regulator and hope for the best?
Thanks!

[docc]

Check the yellow wires at the bottom of the stator (alternator) under the front cover. The do commonly break and may have shorted. They are hard to see all the way in, so you must lie down on your side and trace them in with a good light.

With the regulator that hot, it may be a good bet. Otherwise, Roy will be along presently to get you sorted out.

[fotoguzzi]

Wait, the key was off? it blew just by putting the fuse in? maybe your regulator is fine, something is crossed up, check the ignition switch?
when the starter came loose, how loose, could it have buggered up the electrical connection and it's shorting?

[Kiwi_Roy]

The first thing I recommend with charging problems is to add a good solid ground strap between the regulator and a timing cover bolt.
Grounding is very important as the pulses of current flowing exceed 30 Amps.
While you can afford to loose Voltage in the positive wire from the regulator to the battery any Voltage lost between the regulator case and the battery negative is subtracted from the battery voltage, Loose half a Volt and the battery will be half a Volt lower.
 Charging Circuit Problems.pdf   46.07K   23 downloads

I assume you mean the 30 Amp charging fuse, it should never blow without the bike running, unless perhaps you have a short.
Unplug the red wire at the regulator and put in another fuse, if it blows there is probably a pinched wire in the loom somewhere.
It's also possible someone accidently grounded the battery positive terminal to the ECU case, that causes the ground wire in the loom
to become red hot and melt it's way through the insulation of other wires grounding them
The red wire goes from regulator to fuse to battery.
Reconnect the red wire at the regulator, if the fuse blows it may be a bad regulator but I doubt it.

Roy

[Bugtarget]

Wait, the key was off? it blew just by putting the fuse in? maybe your regulator is fine, something is crossed up, check the ignition switch?
when the starter came loose, how loose, could it have buggered up the electrical connection and it's shorting?

Thanks for the help!
Yea, the key was off and it blew when I put it in. I'll unplug the ignition and then put another fuse in and see what happens. The starter wasn't too loose. a little bit of play but it was being held in with one of the two bolts. The other one was completely unscrewed.

[Bugtarget]

The first thing I recommend with charging problems is to add a good solid ground strap between the regulator and a timing cover bolt.
Grounding is very important as the pulses of current flowing exceed 30 Amps.
While you can afford to loose Voltage in the positive wire from the regulator to the battery any Voltage lost between the regulator case and the battery negative is subtracted from the battery voltage, Loose half a Volt and the battery will be half a Volt lower.
 Charging Circuit Problems.pdf   46.07K   23 downloads

I assume you mean the 30 Amp charging fuse, it should never blow without the bike running, unless perhaps you have a short.
Unplug the red wire at the regulator and put in another fuse, if it blows there is probably a pinched wire in the loom somewhere.
It's also possible someone accidently grounded the battery positive terminal to the ECU case, that causes the ground wire in the loom
to become red hot and melt it's way through the insulation of other wires grounding them
The red wire goes from regulator to fuse to battery.
Reconnect the red wire at the regulator, if the fuse blows it may be a bad regulator but I doubt it.

Roy

Thanks for the help!
The PO did a good job of grounding the reg. Two clean grounds to the alt. cover. I'll try your suggestions

[Bugtarget]

Update-Fuse only pops when red wire is connected. Okay when yellows and black/white are connected only. I disconnected the ignition switch from the harness and the fuse still pops when red is connected.

[Kiwi_Roy]

Update-Fuse only pops when red wire is connected. Okay when yellows and black/white are connected only. I disconnected the ignition switch from the harness and the fuse still pops when red is connected.

Then I'm afraid to say the regulator must be toast, the red wire is connected internally to two diodes, there should be no current flowing back in.
Look at the simple schematic I posted earlier.
I would also inspect the alternator where the wires connect and test for a short, it seems strange to me that the current would flow back through a diode and an SCR.
A stupid question - you don't have the battery connected backwards somehow?

Roy

[Bugtarget]

Update-Fuse only pops when red wire is connected. Okay when yellows and black/white are connected only. I disconnected the ignition switch from the harness and the fuse still pops when red is connected.

Then I'm afraid to say the regulator must be toast, the red wire is connected internally to two diodes, there should be no current flowing back in.
Look at the simple schematic I posted earlier.
I would also inspect the alternator where the wires connect and test for a short, it seems strange to me that the current would flow back through a diode and an SCR.
A stupid question - you don't have the battery connected backwards somehow?

Roy

Thanks for the help, Roy!
The battery is connected properly. I will test the alternator. With the bike completely off, the red wire holds the same current as the battery. Is this how it should be?

[Kiwi_Roy]

[/quote]
Thanks for the help, Roy!
The battery is connected properly. I will test the alternator. With the bike completely off, the red wire holds the same current as the battery. Is this how it should be?
[/quote]

I don't understand, the Voltage at the red wire will be the same but there should not be any current at all, Inside the regulator are a pair of diodes pointing towards the battery (current flow is from regulator to the battery with the engine running)

You said earlier that the fuse only pops when the red wire is connected, I took this to mean when you plug the pair of red wires from the regulator into the single wire of the main loom.

With the bike off there should be zero current flowing in the red wire with or without the regulator connected to it.

A couple of times lately I interacted with owners who had a short circuit that causes the small black ground wire from the ECU to chassis up under the tank burn up. In doing so it can melt through adjacent wires thus shorting them to ground.

When disconnecting the battery it's very important to get in the habit of removing the Negative cable first and reconnecting it last. Do this and the chance of a meltdown are greatly reduced.