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Electrical
Where does this wire go?
Includes Electrical mods, Lights, Stator,
Rectifier, Diagrams, etc

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post #1 of 22 (permalink) Old 08-14-2016, 09:10 PM Thread Starter
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Electrical Nightmare

This may be a longer post, but I want to give you all the information I can to perhaps resolve this issue. I know there are a lot of smarter people than me out there.

I have a 2003 VN750 which I personally have chopped and bobbed; however, the heart of the bike is still there. I purchased the doner bike with a known bad stator. Since then, I have completed the following.

1. Pulled engine and replaced stator...along with the tuxedo modification. Replaced the rotor which was scarred up from stator failure. Like a dumbass, I did not go with the best stator available. It is an Electrosport if it makes any difference.

2. Replaced ignition switch from Handlebar area and went with a simple on-off-accessory key style.

3. Has a NEW Shorai Lithium Battery

4. has a NEW Mosfet Voltage regulator and wiring harness.

5. Has LED Turn signals. Has single bobber tailight. I already bypassed the headlight relay by moving blue wire.

6. This bike no longer has the instrument cluster. It is as simple as a bobber can ge.

The bike runs fantastic at 12 volts and full charge when its cold. After it heats up, it starts to act up and finally quits all together. Today, it killed the battery in a short time....ANF it blew the 30amp fuse for some reason. Never done that before.

Stator is testing good....I think. Getting 50-60 AC Volts through each leg of stator leads. Also, each leg is zero ing out on the ohm meter. However, I am still only getting 12.6-12.8 volts from this new mosfet voltage regulator at any speed. Then, all of a sudden, the bottom will drop out of the battery and voltage will be sucked out of it. Next thing I know, the brand new battery is dead. I even pulled the headlight and tail light fuse to see if it made a difference...no change.

I guess my question is: Is is still possible the stator is acting up even if it is testing good with a meter? Could it be shorting out when it gets hot? Any other ideas?

I am planning on giving my new build to my son who is currently deployed in the US Army overseas. I have about two months to work this out. He has spent the past 6 years protecting me here in the USA, it is the least I can do or him as a surprise when he comes home. I just need to work through this issue.
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post #2 of 22 (permalink) Old 08-14-2016, 09:40 PM
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Yes, the stator can short to ground after it warms up, best to test hot and cold.

The Two Wire mod might help if the stator can pass the hot test. (pinned post in the Electrical section)

2003-19k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Me and Cinderella, we put it all together, we can drive it home, with one headlight.
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post #3 of 22 (permalink) Old 08-14-2016, 10:03 PM Thread Starter
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Interesting

Mr Spockster,
My start button will go dead and I had assumed that it was because the battery was low, however; tonight it still did not work with a fresh battery. I may try this....very interesting.

Could it really be this simple? My luck does not generally run this way.
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post #4 of 22 (permalink) Old 08-15-2016, 03:33 AM
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Ric-Flair,

I've been looking over the electrical schematic, and have some details that might help you track down your problem.

The only way the main fuse can blow is if the stator is charging the battery via the R/R at more than 30 amps (virtually impossible), or if the battery is discharging at 30 amps, which will only happen if there is a short.

If the stator shorts to ground the main fuse would not blow, since the battery can't discharge backwards through the rectifier to the stator (diodes are preventing that from happening).

So, that basically leaves a short somewhere other than the stator. (though you might as well test the stator hot like spockster recommends just to cover all bases)

Spockster's recommendation to try the two-wire mod is a natural place to start, since you say your start button is flaky. A short in the starter relay in the junction box would certainly drain the battery, even with a good stator, possibly badly enough to blow the fuse.

If the two-wire mod doesn't give you a good fix, or fixes your starting issues but not your power loss-when-hot issues, then the problem might be with the FAN switch and/or relay. If there's something wonky with the fan relay such that it shorts out when the bike heats up and trips the thermostat, that sort of describes your situation, loss of all electrical when the bike gets warmed up. Unfortunately a bad fan relay is hard to isolate from the rest of the circuitry since it shares a junction box pin with the rectifier's supply voltage, so rule out everything else first.

1992 US-nonCA * tuxedo mod * r/r relocated

Vulcan slang for newcomers
Service Manual Download
Wiring Diagram + annotations * still undergoing revisions, but still more useful than the generic one. Let me know if you find mistakes or think something additional should be added
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post #5 of 22 (permalink) Old 08-15-2016, 09:23 AM
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Quote:
Originally Posted by Ric-Flair View Post
Mr Spockster,
My start button will go dead and I had assumed that it was because the battery was low, however; tonight it still did not work with a fresh battery. I may try this....very interesting.

Could it really be this simple? My luck does not generally run this way.
Hope the fix is that simple! The mod did fix charging problems on at least two bikes with TPE stators and MOSFET R/Rs.

A couple of ways to try the Two Wire mod ...

Release the wires from the connector and tie them together away from the connector.

-or-

Cut the wires at the connector, leaving enough to splice back on if needed, splice the two wires together away from the connector.

If the Junction Box is causing the problem in that particular circuit, it will work.

If the mod doesn't help, the problem may be elsewhere in the JB or harness, as Thorn has outlined.

2003-19k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Me and Cinderella, we put it all together, we can drive it home, with one headlight.
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post #6 of 22 (permalink) Old 08-15-2016, 09:37 AM
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there is a 3rd way as well

leave the wires on the connector, and splice between them. Thats how mine is done.

2005 VN750
33.5k and counting
original stator (as far as I know)
ear shave, using Uni pod filters.
Pickup coils at 0.020 gap
VN900 seat mod
led's turns front and rear
MOSFET R/R, mounted under left side cover
2-wire mod to bypass clutch/neutral nanny switches
removed side stand switch.
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post #7 of 22 (permalink) Old 08-15-2016, 10:08 AM
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Quote:
Originally Posted by michiganteddybear View Post
there is a 3rd way as well

leave the wires on the connector, and splice between them. Thats how mine is done.
True, that will make the start button work, but it doesn't isolate the problem circuit/relay in the JB.

2003-19k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Me and Cinderella, we put it all together, we can drive it home, with one headlight.
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post #8 of 22 (permalink) Old 08-15-2016, 10:30 PM Thread Starter
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On Second Thought

The more I think about it, the more I am going to go through some of my work a little more.

I replaced the key switch mounted on the handlebars with a simple three position key switch (on-off-accessory) Of course, wires had to be grouped and attached onto certain key switch positions (schematics and info I obtained here on this website...SlimVulcanRider I think) anyway, I am wondering if perhaps one of these connections could be shorting out.

ALso,

I did wire the fan onto a manual toggle switch. However, I am not sure just where I am drawing the power from...just a hot lead probably. I may go back and remove the tank, and cut the wire loose. I could run a fused wire directly to the battery pretty easily. This would take the fan off the bike's wiring all together. The more I think about it, something could be shorting and drawing the battery down...and this would also explain the blown 30amp main fuse too, right?

Feeling a little better about this...hopefully I will figure this out. My son is due back in the US on September 30th. I need to be ready for him. I dream of giving the bike to him the day he returns from overseas. #Ranger #GoArmy #Infantry
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post #9 of 22 (permalink) Old 08-15-2016, 10:58 PM
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If you've already got the fan on a manual switch, pull the wires off of junction box pins 4 and 5 (black/yellow, blue wires on ten pin connector). That'll remove any path to ground from the potentially faulty fan relay or cooling fan switch/thermostat. Rule out as many variables as possible when chasing gremlins.

Since you're dealing with a short that is shunting enough current to blow the 30 amp main, I'd be cautious about wiring anything directly to the battery. That fuse prevented a disaster, and you don't know if its the fan motor that did it or not. Wherever you've wired your manual switch in, leave it there for now. Either it's not causing any problems, or it IS causing problems and the fuse box is saving your bacon!

It would be good from a diagnostic standpoint to know which wire you spliced into, though, so if you find it, post it.

1992 US-nonCA * tuxedo mod * r/r relocated

Vulcan slang for newcomers
Service Manual Download
Wiring Diagram + annotations * still undergoing revisions, but still more useful than the generic one. Let me know if you find mistakes or think something additional should be added
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post #10 of 22 (permalink) Old 08-15-2016, 11:30 PM Thread Starter
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Very helpful advice Mr. Thorn. I will indeed pull the wires from the 10 pin connector. I am so stupid sometimes.

If I ran a new wire FROM the battery....through an inline fuse link ...to the toggle switch....then to the fan...that would be safe, correct? The fan is just grounded to the frame.

I too am anxious to see just what wire I used to power the fan. Like i said before...the bike runs fantastic, but these electrical gremlins are popping up now. Thinking about putting a toggle on the aftermarket headlight ground wire too. I just want to eliminate any extra draw on the battery that I absolutely do not need. Florida does not require a headlight to be on during the day. Any negatives?
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