[cjlucas27]

So I have been working on my bike after the person before me wrecked it. My first of a few problem is a charging problem I have where the bike would only run on battery power, once it died the bike died. I checked the resistance on the stator and it was 3.0 ohms, as far as I know it should be about 0.3. I replaced the stator, I replaced the rectifier and the plug that goes to it (3 of the 5 connections on the plug were corroded beyond saving). I rode the bike about 20 miles just fine, near the end of the ride, the person riding with me noticed my tailights were going dim. I got home and the bike was back to not charging. The resistance was back to being at 3.0. It has a new battery as of today and I’m at a loss.

Side note, I’m not sure this could be tied into any of these problems but I have also bought 3 starter relays which have all broken within a few uses.

 

[txwaver46]

i think you gotta have a problem with the wiring harness. you already replaced most parts related to charging system. maybe its a loose ground or bad connection.

 

[cjlucas27]

After digging into the wiring harness, I found a few ground wires, 5 specifically that all come together, one from the rectifier (The one I am holding), one from the plug that goes to the gas tank fuel level sensor (small wire on top) and the others are unknown. They are all melted. After cutting them all apart and testing each wire, 2 of the wires are getting power through them. The one on the left in the picture is getting 12v and the one on the bottom right is getting 0.15. I tested by holding the wire to one side of a volt meter and the other to the negative post of the battery. I believe I now have to go further into the harness to find why these grounds are getting power.

 

[gpounce]

Voltage from the black wires to ground isn't a bad thing, it means the device on the other end of the wire is powered, you are seeing the completion of the circuit to ground. Those wires are sure a mess, I think the next step is to cut back to good insulation and splice in enough wire to remake the connections. Do you have any indications what messed them up so much eg improperly resting against something hot?

Are you sure the starter relays have gone bad, or could it be that when you replaced them you disturbed wiring so that some marginal connection was OK for a little while?

 

[cjlucas27]

I felt that the wires were melting because of the wires that have power. I found that when I tried to test a wire by disconnecting it from the splice of 5 wires and rather touching it to the negative post on the battery, the wires would get hot in my hand, not because it’s next to the motor, the whole wire would heat up (bike is on, motor running) and melt off the end of the wire. I held the rectifier wire to the battery and not only did that wire get hot but the other 4 did too. This might have happened because I tried something pointless, I don’t exactly understand electricity and wiring that well. These wires may be getting hot because of something unrelated to the power running through the 2 of 5 wires. I’m not exactly shre

 

[cjlucas27]

Going back to the starter relays, whenever I press the starter button, the only thing the relay does is makes one click once the button is pressed, nothing more. The only way I have been able to start the bike is the screwdriver trick by bridging the relay. I don’t think that it could be messing with any wiring outside of it, all wires around it seem to be normal. Now that I think about it though, I’m curious to know if there is a ground wire that runs into the plug that plugs into the relay. That ground could be another one of the few in the picture and a bad ground could make it go bad maybe? Or just malfunction even.

 

[cjlucas27]

I think I have found what each of the wires are for, one is for the gas tank fuel sensor, one is for the rectifier, one is coming from the plug for the front cluster it has 12v through it (I’m assuming the headlights because now that it’s disconnected, they are off but the tach and speedo is still working), the fourth goes to the tailight. The last is unknown, it’s got 0.15v going through it

 

[gpounce]

Wires should not be getting hot, so there are definitely problems, likely several in combination. Sounds like the rectifier is likely blown, so I'd suggest disconnect that to start breaking the problem down. Also confirm the correct value fuses- should be 30amp for the main fuse the others are labelled. Can you post a pic of your meter- it may be possible to set it to measure current which we can use to identify which of the wires carries excessive current.

 

[cjlucas27]

I can confirm the fuse in the starter relay is a 30 amp. I traced the ground wire with 12v all the way back to the ground that comes out of each headlight bulb, after cutting the ground off from the headlight off of the rest of the bike, the ground wire near the rectifier that runs to the headlight becomes 0 volts as it should. Next I checked the ground wire that I cut apart and it seems that power from the low and high beam is running into the headlight and coming out on the ground (ground gets 12v) but it’s in both headlights. (When the grounds for each headlight are cut off from the rest of the bike, those grounds are reading 12v)

The voltmeter I’m using looks like the picture attached and I have it set to the “20” position under the DCV section.

 

[gpounce]

so that meter will read current but maxes out at 10 amps which could easily be exceeded by a short somewhere, so I don't think measuring current with it is a good choice right now. Another possibility, if you have the stuff is to set up a spare 12v automotive lamp eg taillight or headlight with 2 wires. Use it as a probe; one lead to ground/negative, the other to test the harness leads in question; if the bulb glows bright then you have found a high current connection to ground (expected for the headlights, but not for the other ones)- the win is that the bulb reduces the current so as to not damage anything- whereas relying on the wire getting hot is certainly overloading something else.

If you detach the rectifier ground from the cluster, do the headlights etc work and wires not get hot?

The headlight circuit (and gas empty sensor) are both simple circuits so I would not expect trouble to be likely there- OTOH the rectifier is a known source of trouble so I'm kind of looking at that.

 

[cjlucas27]

After detaching the rectifier or any of the other wires, the one wire coming from the cluster gets hot if it touches a wire that is reading 0v like the others. Standing alone the wire does not get hot, but reads about 12.5 volts if one lead goes to the wire and one lead goes to the negative side of the battery.

 

[gpounce]

The wire is getting hot because current flows thru it. It sounds like only one wire from the cluster gets hot- meaning if you break apart the cluster and test each one individually, there is only one that gets hot?

Have you identified where that lead goes?

I did some digging in the service manual, there are a couple tests we can use your meter for, to look into the starter relay and starter relay cutoff relay- possibly interesting to probe into that part of the harness as well.

 

[cjlucas27]

I ripped apart the harness all the way to the cluster and found that the one wire getting 12 volts is because of the ground wires to the head lights. Both ground wires coming out of the headlights are reading 12 volts, once’s disconnected from the rest of the bike, the wire near the rectifier once reading 12 now reads 0

 

[gpounce]

OK, so have you have identified the wire that gets hot and where it leads?

Or are you saying that wires no longer get hot if the headlight ground leads are disconnected?

 

[cjlucas27]

The wire no longer gets hot because it is disconnected from the headlight ground, I believe the headlight ground will get hot through if it is grounded on the frame or battery post just like the ground wire it used to be connected to did when I grounded it on the frame or battery

 

[gpounce]

So if you reconnect the bundle, leaving the headlight grounds out of it, nothing gets hot?

 

[cjlucas27]

I believe so, I can double check when I get to where the bike is later but I’m going to answer yes because the rest of the wires read 0v when reconnected excluding the headlight grounds

 

[gpounce]

So assuming the hot wires are headlight related, are these OEM headlights or something else? And when you do ground the headlight leads, do they come on (low and high beam)?

 

[cjlucas27]

They are OEM and when grounded the headlights come on low and high beam but that’s when the grounds from the headlight get hot.

 

[cjlucas27]

Also I’m not sure if it matters but with the high beam button pressed on the handle bars, it’s actually the low beam and vice versa, if I switch it to low beams on the handle bars the high beams on the headlights come on