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Discussion Starter #1
I have been having a lot of trouble this year so far. I was riding and the bike began to run poorly with all lights shutting off. The regulator still being under the bettery box had a lot of batter acid and the connections did not look good. Long story short I just put on a new regulator but now the 30amp fuse is blowing every time I put one in. Why is this? with the key off it will still blow any help would be great
 

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You have a short somewhere. Wish I could be more specific about where to start looking.
Does the 30 amp fuse blow as soon as you install it, or does it take a few seconds?
 

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my guess is you have a dead short someplace. A little investigation with a continuity tester should find the problem. I would start with the white wire leaving the JB.....It goes to both the R/R and the ign. switch. I bet it is grounded someplace.
 

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Discussion Starter #4
It's as soon as I put it in like as I am pushing it in with key off. I'll check them out thanks I was expecting it was because of a short but wasn't sure where to start looking thanks
 

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my guess is you have a dead short someplace. A little investigation with a continuity tester should find the problem. I would start with the white wire leaving the JB.....It goes to both the R/R and the ign. switch. I bet it is grounded someplace.
And I'd almost bet money that grounded spot is in the ignition switch wiring harness, where it goes around the steering head to the bracket where it plugs into the rest of the harness; wouldn't be the first time I've seen that on these bikes.

I've also got a wiring harness out of an '86 out in the shed, that the white wire and a black/yellow ground wire are melted together right where the main harness crossed the frame under the seat.

The absolute best place to start tracking electrical problems like this is with a continuity tester, DVM, and the manual with a wiring diagram.
 

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And I'd almost bet money that grounded spot is in the ignition switch wiring harness, where it goes around the steering head to the bracket where it plugs into the rest of the harness; wouldn't be the first time I've seen that on these bikes.

I've also got a wiring harness out of an '86 out in the shed, that the white wire and a black/yellow ground wire are melted together right where the main harness crossed the frame under the seat.

The absolute best place to start tracking electrical problems like this is with a continuity tester, DVM, and the manual with a wiring diagram.
This!
 

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I have a question. Do you know if the fuse was blowing before you changed the regulator? The way I read what you said maybe it started after u changed the regulator. However maybe the fuse blew and then your problems started. You could try disconnecting the R/R plug and see if your fuse still blows, if it doesnt you may have a bad R/R. If it is definatly is a wire problem you need to get some schematics. You would have to review more then one since a single schematic does not tell the whole story, for example the ignition schematic will only show in referance to the ignition, the charging schematic in referance to the charging. There are several connectors through out the harness, looking at the schematics you could systematicly disconnect connectors and see if the fuse still blows doing this you can eliminate where the problem is or is not. WARNING its probably not a good idea to keep subjecting your wires to a shorted condition. So you can check continuity from the system side of the fuse or use the WHT wire on the JB 8 pin connector to ground then do what I mentioned earlier to isolate where the problem is. FYI this wire also goes to both cylinder ignition coils and the IC Ignitor, so i would disconnect these along with the R/R to take these components out of the equation. Please let us know what you found
 

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IIRC, if the key is off there is only one circuit after the 30A fuse that is 'hot' and that's the white wire leaving the JB. It goes from there and splits off to the R/R and feeds the ign switch. Your problem is in this circuit. Should be easy to find.
 

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Discussion Starter #9
I have a question. Do you know if the fuse was blowing before you changed the regulator? The way I read what you said maybe it started after u changed the regulator. However maybe the fuse blew and then your problems started. You could try disconnecting the R/R plug and see if your fuse still blows, if it doesnt you may have a bad R/R. If it is definatly is a wire problem you need to get some schematics. You would have to review more then one since a single schematic does not tell the whole story, for example the ignition schematic will only show in referance to the ignition, the charging schematic in referance to the charging. There are several connectors through out the harness, looking at the schematics you could systematicly disconnect connectors and see if the fuse still blows doing this you can eliminate where the problem is or is not. WARNING its probably not a good idea to keep subjecting your wires to a shorted condition. So you can check continuity from the system side of the fuse or use the WHT wire on the JB 8 pin connector to ground then do what I mentioned earlier to isolate where the problem is. FYI this wire also goes to both cylinder ignition coils and the IC Ignitor, so i would disconnect these along with the R/R to take these components out of the equation. Please let us know what you found
This has started after the replacement.... The bike does turnover without the regulator hooked up, so what would that mean? I have had two diffrent regulators and both have the same problem with the fuse blowing
 

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Discussion Starter #10
Blows when the black/yellow wire is hooked up. The rest can be hooked up and it's fine as soon as black/yellow is it blows
 

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Ok first off, the bike can turnover just fine without the R/R has nothing to do with starting or the engine running, its sole purpose in life is to change the AC voltage coming from the stator and turn it into regulated DC voltage for the operation of the bikes accessories and to charge the battery. The blk/yl wire is the ground, are you saying when you hook up that wire to the R/R is when it blows? If so, does the fuse blow if only the blk/yl wire is hooked up with all others not connected. We are talking at the R/R connector correct?
 

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Discussion Starter #12
Thank you for responses. With just black and yellow it does not blow. The new regulator I got is off of a ninja I was told they are the same... Because of not blowing with r/r disconnected means there are no shorts in the rest of the system right?
 

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Im lead to believe that there would not be any other shorts in the system. Im curious what the resistance is between the terminal that you hook up the blk/y wire and the terminal you hook up the white wire. You might find it is a low resistance. Try checking it two times, swapping the positive and negitive meter lead. This is what the manual says the readings should be with the neg meter lead on the terminal for the wht wire and the pos meter lead on the terminal for the ground wire you should have infinate resistance when you swap the meter leads you should have .4-2k OHMS. there are some other checks, but i listed the link for a manual in the next reply. Im not for sure but i would think the two regulators are different. From what ive read on here the mosfet R/R is a good replacement. Thats what i put on my bike. The kit is about $124.00 here is a couple links, one is how i did my mosfet install the other is the link to the website where you can get one.

http://www.vn750.com/forum/showthread.php?t=18361

http://roadstercycle.com/Shindengen%20FH012AA%20Regulator%20upgrade%20kit.htm
 

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Did a little research, maybe the R/R's are the same. Does the connector hook right up or did you have to rewire for a different connector. Im looking at the manual, about testing the R/R. First of all if your looking at the R/R with the connector lock tab facing down. The 3 top wires are the yellow stator wires, bottom row left to right blk/y, brn, white. Here is a link to a free download of the manual I have. learned about it on here. its pdf format so you would have to have acrobat reader. about 112M file size

http://www.tocmanufacturing.com/Products.htm
 

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Discussion Starter #15
Maybe that's is the problem. I have been told to hock them up the other way with the blk/y being on the right towared the back of the bike. So it should be toward the front of the bike being the left.
 

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keep in mind i gave you the information on the stock R/R from the manual. R/R's are full of diodes, if there biased the wrong way then current will flow. Maybe your biasing the diodes the with the wires being swapped causing the diode to conduct. you can figure it out with a multimeter. look at what i said a couple replies up, about checking the resistance inside the R/R. Read it out the way you had it hooked up when it was blowing fuses. If it seems backwards maybe you do have the wires swapped.
 
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