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Wire Burned out

C

cayuse60

Maine Rider
What electrical malfunction may have caused the alternator to battery feed wire to burn out?:dunno

TIA---tim
 
Last edited:
The first thing that comes to mind is that there is a shorted diode in the alternator. Are you sure the wire is burnt all the way to the alternator connection? It may have gotten a bare spot between the battery position and ground somewhere before the alternator. Since there is no fuse on this wire it would explain why it burnt up instead of blowing a fuse.

If you have an ohmmeter you can put it on the alternator connection (remove the battery wire first) and read the resistance to ground. This would tell you if you have a shorted diode. Measure the resistance with the ohmmeter leads both ways. One way should show infinte resistance and the other way will show a low resistance. The actual low resistance value is not very important for your problem. The infinte resistance if not present will be your problem.
 
Its probably the cable going to the starter relay.....just got hot during a session and melted.

What's with that battery? The terminals are reversed from normal.
 
jdiaz said:
Its probably the cable going to the starter relay.....just got hot during a session and melted.

What's with that battery? The terminals are reversed from normal.
Click to expand...

It is the connection to the alternator from the positive battery terminal.
 
Jon Diaz is right about the battery connections appearing to be backwards. If you hooked up the negative lead to the alternator that would cause the wire to melt and probably blow the diodes in the alternator.
 
kioolt said:
The first thing that comes to mind is that there is a shorted diode in the alternator. Are you sure the wire is burnt all the way to the alternator connection? It may have gotten a bare spot between the battery position and ground somewhere before the alternator. Since there is no fuse on this wire it would explain why it burnt up instead of blowing a fuse.

If you have an ohmmeter you can put it on the alternator connection (remove the battery wire first) and read the resistance to ground. This would tell you if you have a shorted diode. Measure the resistance with the ohmmeter leads both ways. One way should show infinte resistance and the other way will show a low resistance. The actual low resistance value is not very important for your problem. The infinte resistance if not present will be your problem.
Click to expand...


Did the checks with an anolog Ohm meter...infinite resistance positive to ground...some resistance negative to ground.

Could this have been caused by connecting a battery charger to battery while still in the bike with the ground still connected?
 
kioolt said:
Jon Diaz is right about the battery connections appearing to be backwards. If you hooked up the negative lead to the alternator that would cause the wire to melt and probably blow the diodes in the alternator.
Click to expand...

This K75 has the battery ground cable on the left side and the positive on the right side (side where alternator is located)? I'm guessing this is correct. :dunno Bike starts ok but I have no charge from the alternator. Bought bike in this condition.
 
cayuse60 said:
Did the checks with an anolog Ohm meter...infinite resistance positive to ground...some resistance negative to ground.

Could this have been caused by connecting a battery charger to battery while still in the bike with the ground still connected?
Click to expand...


If I'm understanding your reply you put the ohmmeter positive lead on the alernator and the ohmmeter negative lead on ground and got infinite. If so then that is a good reading. With the leads reversed you got a low reading. That is also good. I have NEVER unhooked a battery just to charge it.

Just to be sure you know how to use an analog ohmmeter. When you say you got infinite resistance you mean the needle didn't move?
 
kioolt said:
If I'm understanding your reply you put the ohmmeter positive lead on the alernator and the ohmmeter negative lead on ground and got infinite. If so then that is a good reading. With the leads reversed you got a low reading. That is also good. I have NEVER unhooked a battery just to charge it.

Just to be sure you know how to use an analog ohmmeter. When you say you got infinite resistance you mean the needle didn't move?
Click to expand...


Positive to B+ (output connection), negative to alternator case ground = 63k ohms. Positive to alternator case ground, negative to B+ = no reading (open circuit).
 
Your readings look to be backwards to me. I have been told that some multimeters actually have the polarity of the leads reversed when in the ohms function. I will have to assume that that is what we have here.

Does the charge light in the instrument pod come on when you turn the key on before starting the bike? A blown charge indicator light can cause the alternator not to charge.
 
K 75 harness

Do you need a harness? I hav a complete one that is in excelent shape if so email me on this site I will get back to you :thumb
Mike R
 
kioolt said:
Your readings look to be backwards to me. I have been told that some multimeters actually have the polarity of the leads reversed when in the ohms function. I will have to assume that that is what we have here.

Does the charge light in the instrument pod come on when you turn the key on before starting the bike? A blown charge indicator light can cause the alternator not to charge.
Click to expand...

I just rechecked my readings with my ohm meter (it needed a new battery), 1 k ohms in both directions B+ to case ground. I'll need to tear the alternator down and check the individual diode plates, but I think they are fried, also.

I've replaced the burnt wiring and connectors and I have a steady no charge (battery) light with 12.2 volts off a fully charged battery.

I do have a spare alternator. It reads from B+ to case ground 3.5 k ohms in one direction and no continuity in the other.

I guess I'll be changing out the alternator, along with every other periodic maintenance task.

Good way to learn what makes this machine tic. :)

Thanks for all your insights.----tim
 
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