Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums - Reply to Topic
Electrical
Where does this wire go?
Includes Electrical mods, Lights, Stator,
Rectifier, Diagrams, etc

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  Topic Review (Newest First)
09-09-2018 03:48 AM
Thorn Thanks for posting back with your find. Always good to know what to look for "next time"!
09-08-2018 06:58 PM
Darren P Smith Turns out I'm a bigger idiot then I gave myself credit for. The stator I bought was carlise I believe idk if that's a cheap brand or not but apparently the screw the holds the wire strap to the armature of the stator somehow would ground out when I installed it well long story short I fried that stator bought a new one removed the screw installed it and now everything is fine. I hate that I wasted everyone's time, but thanks for everyone's help. Hopefully in the future we/I will know to check for that.
08-27-2018 02:00 AM
Thorn Might want to double-check if your high/low beams are reversed. I think it should be blue spliced to blue/orange instead of blue/yellow. Either way, that wouldn't be causing your ground to overheat, so the RLU seems to be unrelated to the bigger problem. If you haven't done it yet, follow Spockster's advice and do the blue-wire mod along with the optional step of removing the yellow wire from the stator that triggers the headlight relay, since that is an avenue for unregulated voltage to get into the electrical system.
08-26-2018 07:20 PM
Darren P Smith Sorry it's been so long I've been pretty busy lately. The wires I spliced together for the rlu is dark blue and blue with orange stripe.
08-20-2018 10:29 PM
Thorn Yeah, the 'T' from one of the three yellow stator wires to the JB is a definite avenue for unregulated power getting into the circuitry, especially if the headlight relay has gone bad (possibly what cooked the reserve box).

HOWEVER, looking at the symptoms, I think there's a short from a live wire to the frame of the bike. After the engine has been started, current should be flowing backwards through the battery, with the current flowing from the negative terminal towards the R/R's ground wire. I suspect the thick wire between the negative terminal and the frame is that beefy in order to provide the cranking amps to the starter motor, and that once the engine is running, it is well over-sized. With a large current dumping into the frame from somewhere, though, that wire is running at capacity, and the smaller 14 gauge between the beefy wire and the rectifier can't handle the load.

A pinched positive wire near the stator does make sense, since none of the positive wires are melting, only the ground (as current dumps from the frame to the rectifier's ground/negative terminal). It would also explain why you have low/no voltage at the positive terminal of the battery since there is a better path to ground than through the resistance of the battery.

I don't think the pickup wires would have enough current to melt anything since I think they're basically just a hall effect sensor. The short is more likely one of the yellow stator wires, or maybe a short in the coil wiring itself (but that would likely cause a dead cylinder?)

When you added a jumper to bypass the RLU, which wires if any were removed and which were spliced?
08-20-2018 08:46 PM
Spockster Good post Thorn, it's got me thinking I should check the old r/r wiring on my bike, even though it's unplugged. That brown monitor wire shows up as red/white at the ignition switch (in the color diagram), but the brown runs straight there, and to the switch.

Was reading back and picked up on this ...

Quote:
Once the bike shuts off with the key still on or not the wire starts cooling down.
This bike also had headlight problems .. RLU problem.

The smoking wire cools down when it's not charging. ???

If the brown at the r/r checks out ok... also check the stator wires. Maybe try the blue wire mod? That's a circuit that's only working when the engine is running and involves a relay in the Junction Box.

Could there be AC stator volts hitting some of the other JB circuits?

Could a pickup coil wire be pinched at the stator plate? If it was on the same coil with the black/yellow, would that cause it to heat up? (only when running)

Can't rule out headlight wiring yet either I guess. Your headlight is off after you shut down the engine?
08-20-2018 12:49 PM
Thorn Ok, here's a crazy theory I've been kicking around for a while regarding these bikes and why we fry so many stators/rectifiers:

Any time the electrical goes flakey, everyone immediately says "It's the ignition switch." But what nobody brings up is that the monitor wire for the R/R splits directly off of the ignition. That lead is just as likely to go bad as any other, and would cause the R/R to dump a higher-than-wanted voltage into the system, and without the protection of the 30amp main fuse. There wouldn't necessarily need to be a bad connection anywhere to have the resulting high currents start melting wires. Am I way out in crazy town with this line of thinking?

@Darren: were you able to measure voltage between the v+ and ground of the rectifier when running? What's your resistance between rectifier's monitor pin and v+ pin when engine is off but ignition is 'on'?
08-20-2018 07:51 AM
Darren P Smith I'll take a look at the repair manual and see. Yes the bike is running on both cylinders. So the general consensus is I have a bad wire somewhere, but am I looking for a bad ground?
08-20-2018 07:28 AM
Spockster Could also ohm test the pickup coils, just to rule out a problem there. Those wires are known to break.

Is the engine running on both cylinders?
08-20-2018 06:42 AM
Spockster In section 15-24 of the repair manual there's a chart for ohm tests on the IC. I'd go through those tests to see if the IC is ok.

edit: I recall something about the spark being triggered through ground, not sure but continuity on that ground wire may be intermittent by design. Seems the discussion was the ground at the ignition coils, so I may wrong.

You might be able to roll the engine over with the ohm meter connected at that ground, and see if there's any continuity then.
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