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Discussion Starter · #1 ·
I have a nagging problem with my 84 GPZ 750 , it's an intermittent charging issue. Has anyone had a problem with the fuse box causing a problem with charging. Wiring from regulator goes into the fuse box then is dispersed into the battery. Seems everything is good up to the fuse box
 

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What you have is properly called the Junction Box or J-Box for short.

Sometimes the tabs that hold the fuses get spread out so they don't maintain a consistent contact. When you pull or insert a fuse do they all feel like they encounter the same friction going in or out?

A few of mine were loose so I took the J-box apart, gave everything a good cleaning, tweaked the contacts with a pair of pliers to increase the clamping force and its all good now.

I would also carefully inspect the three yellow wires coming from your alternator and especially the first connector for corrosion or signs of heat. This is a common point of failure on many vintage bikes, not just Kawis.
 

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Honda had a problem where their fuses boxes started conducting electricity, and shorting the bike dead. I finally just took mine out, and used bullet connectors with in line fuses.. As WFO-KZZ wrote, you might have to go through and check each connection, make sure there is nocorrosion anywhere, that stuff can conduct electricity. If you can't find the problem, you could try doing what I did. If the bike works, find a new fuse Junction Box on EBAY, or just mark the wires, and go without it. ;)
 

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Discussion Starter · #4 ·
Honda had a problem where their fuses boxes started conducting electricity, and shorting the bike dead. I finally just took mine out, and used bullet connectors with in line fuses.. As WFO-KZZ wrote, you might have to go through and check each connection, make sure there is nocorrosion anywhere, that stuff can conduct electricity. If you can't find the problem, you could try doing what I did. If the bike works, find a new fuse Junction Box on EBAY, or just mark the wires, and go without it. ;)
Trust me when I said everything was checked and double checked from connections to grounds to continuity even un taped the main wire harness to check the 3-way connection of the positive wire coming from the regulator. voltage is constant when probing the charge wire coming out of the regulator with a multimeter. Gotta be that **** fuse box or whatever you want to call it, but thanks from all of you for your suggestions.
 

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Though I agree with my friends above, and I trust that you're capable of checking all the connections and components, I remain puzzled by the complaint: "an intermittent charging issue".
Would you mind elaborating with some detail about symptoms, when they occur, some readings of amps and volts, etc? I admit that I'm much more familiar with Yamaha, Honda and Suzuki electricals, and cannot recall anyone running the charging system through any fuses, or relays in a fuse box, but I'm certainly prepared to learn about the Kawasaki system, and perhaps we can work through some basic troubleshooting, and find the fault(s). BTW, sweet lookin' bike!
 

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The 1980"s was when I found out that someone at Suzuki did not understand just how lousy their charging system was for the GS series of motorcycles. Suzuki would Rectified all 3 legs of the Stator, but would only Regulate 1 leg of the Stator. This left two legs of the stator swinging up and down on their output. I replaced my stock Horns with Fiamm Horns, and they drew a lot of current. This is when I started having problems on my bike. They also ran the stator wires through the Harness with around 6 feet of wire that was too small in gauge. After numerous break downs, where I thought I was runnning fine, but turned out I was running off of the battery, I found the problem. I decided keeeping the bike original wasn't going to work for me anymore (I purchased it new), so I followed the 3 Stator wires, purchased a huge beefy Voltage Regulator, it came off of some big bore 1100 cc Kawasaki (EBAY special), and ran, with as short as necessary, the 3 stator wires to the Kawasaki Voltage regulator, which I mounted right next to the batter, with a custom bracket, and ran the Positive + lead and Negative - Lead directly to the battery (around 8" inches long). I had installed a "Nosports" Stator, which gave 20% more voltage, and "Voila', no problems, for the last 10 years.

If you bypass everything "Ruductio ad absurdum" (Reduce to absurdity) then your bike will charge. If not, either the voltage regulator/rectifier is shot, or the stator is shot(sometimes stators go bad under load and heat)

It's kind of an "Occam's Razor" thing,( ""entities should not be multiplied beyond necessity" ) after everything is ruled out, it has to be what's left that causing the problem. If parts of the bike aren't working, then you attach one by one till they work, or you find the faulty component blowing the fuse. So many Suzuki's were sold cheaply back them, so many GS1150, going for $1200 to $1500 bucks, because of this electrically bad design, I wish I had purchased them as an investment, as they have now shot up in price. :)
 

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Discussion Starter · #7 ·
Though I agree with my friends above, and I trust that you're capable of checking all the connections and components, I remain puzzled by the complaint: "an intermittent charging issue".
Would you mind elaborating with some detail about symptoms, when they occur, some readings of amps and volts, etc? I admit that I'm much more familiar with Yamaha, Honda and Suzuki electricals, and cannot recall anyone running the charging system through any fuses, or relays in a fuse box, but I'm certainly prepared to learn about the Kawasaki system, and perhaps we can work through some basic troubleshooting, and find the fault(s). BTW, sweet lookin' bike!
The intermittent charging issue is just that. At any given moment hot or cold low revs or high revs she'll stop charging then start charging again on and off.I can see that at will by pushing the volt button on the tach and i have verified that reading with a multimeter at the battery it deffintly seems to be a connection problem but i have along with another old mechanic friend of mine have searched and searched to no avail by the way new stator and regulator
 

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Do you have the factory service manual? If so, please post the charging circuit diagram. I have the big brother to your 750, the 1984 GPz900 and could post my diagram but its not guaranteed to use the same circuits.
 

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Discussion Starter · #12 ·
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There is a 4-prong connector the plugs into the fuse box this connector contains the white positive wire coming out of the regulator a ground from the regulator and a wire that goes directly to the battery and a auxiliary wire that dead ends in the headlight housing, that's where I think that connection transferring through the fuse box is the problem
 

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Discussion Starter · #14 ·
Here’s the wiring gut the A1 US model and the key.

Almost a match but as you can see the charge wire going to the battery is coming out of that 4-prong connector in the fuse box as is the ground wire. Wiring going into that 4-prong connector is coming from the regulator Thank You for the schematic
 

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Here is the kind of diagram I was hoping for. It isolates the charging circuit from the entire wiring diagram making troubleshooting so much easier. Note, this is for my 1984 GPz 900 and may not be identical to the GPz750.


Rectangle Schematic Font Parallel Engineering
 

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Discussion Starter · #16 ·
Here is the kind of diagram I was hoping for. It isolates the charging circuit from the entire wiring diagram making troubleshooting so much easier. Note, this is for my 1984 GPz 900 and may not be identical to the GPz750.


View attachment 45341
Here is the kind of diagram I was hoping for. It isolates the charging circuit from the entire wiring diagram making troubleshooting so much easier. Note, this is for my 1984 GPz 900 and may not be identical to the GPz750.


View attachment 45341
Excellent !
 

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Here is the diagram for alternator to regulator for the 84 GPz 750.

The right hand yellow wire goes directly to the J-Box from the regulator. The white wire goes to the ignition switch and to the J-Box. The Brown/White wire goes to lots of places and also to the J-Box. The Black/Yellow wire goes to lots of places and also to the J-box. Not sure if this helps.

Rectangle Font Parallel Cylinder Slope
 

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