The Two Wire Mod - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Electrical
Where does this wire go?
Includes Electrical mods, Lights, Stator,
Rectifier, Diagrams, etc

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post #1 of 175 (permalink) Old 09-24-2015, 07:54 PM Thread Starter
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Lightbulb The Two Wire Mod

Edit March 2016: So far, we know Kawi used black/red or all black for the wire running to the 10-pin JB plug from the start button. This has caused some confusion and errors applying this mod in some cases. This is probably the reason for the headlight problems later in this thread. Will try to get a couple of pics and pin locations up as soon as I can post pics again.
__________________________________________________ _______________

Edit June 2017 - Watch this video before beginning: https://www.vn750.com/forum/19-electr...wire-mods.html

* Be aware that this mod disables the neutral start switch. Your bike will start in gear with the clutch engaged after doing this mod.*

Posting this so more people may become aware of it, recommending it as a preventative mod that could save your stator, or resolve some of the other problems it covers. The mod can also keep you from being stranded.

The Two Wire Mod

1) At the Junction Box, find the 10-pin connector (smaller of the two)

2) Locate the yellow/red stripe and black/red stripe wires (Kawi also used all black instead of black/red)

3) Remove the two wires from the 10-pin plug

4) Splice the two wires together securely and insulate properly

edit: This is the color diagram I'm using:



Link to High-Res Color Wiring Diagram: https://drive.google.com/file/d/0B23...RmQ2dzMGs/view

That's it!

What The Two Wire Mod Covers

1) Start Button Failure

2) Low Peak Charge Voltage

3) Charging System Brownouts - (volts dropping well below peak voltage for periods of time)

4) Charging System Failure to charge with a good stator, R/R, etc.

5) Possibly improves ignition voltage. The yellow/red branches off before the Junction Box and feeds into the IC Ignitor box. Hot and cold starting both improved on my bike.

This mod is bypassing unidentified faults and future faults with these circuits in the Junction Box.

Let us know if this works for you.

michiganteddybear did this 1 1/2 years ago for his start button.

I have the TPE/MOSFET and this mod cured charging system brownouts, low peak charge, dead start button, and hot/cold starts on my bike.

thtanner has the TPE/MOSFET that wasn't charging at all, both of ours are at 14.5v now.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf

Last edited by Spockster; 04-08-2018 at 08:28 AM. Reason: added wire color info ... restored color wiring diagram
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post #2 of 175 (permalink) Old 09-24-2015, 08:02 PM
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Sticky Sticky Sticky Sticky Sticky Sticky Sticky Sticky

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post #3 of 175 (permalink) Old 09-24-2015, 08:04 PM Thread Starter
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Cool

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Originally Posted by OleDirtyDoc View Post
Sticky Sticky Sticky Sticky Sticky Sticky Sticky Sticky
x2 sticky... .. and thanky ODD.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf
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post #4 of 175 (permalink) Old 09-24-2015, 08:43 PM
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I first did this mod due to the start button intermittently failing to crank engine.. a couple well placed whacks on the left side cover (where junction box lives) sometimes brought life back to it.. traced it back to a failing start relay inside the J/B. The mod has totally removed that issue from my bike.

on a side note, and it wasn't checked at the time (not a concern when I did mod), I don't know what my charge voltage was, but I have stock oem stator, and at that time the stock oem r/r. since the mod I have replaced the r/r with a mosfet (still have stock stator), and I believe my charge voltage is around 13 at idle, but climbs to 14+ by the time its turning 2k rpm..

2005 VN750

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post #5 of 175 (permalink) Old 09-24-2015, 09:16 PM
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Sticky Sticky Sticky Sticky Sticky Sticky Sticky Sticky
Done.

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post #6 of 175 (permalink) Old 09-24-2015, 09:29 PM
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Thank you

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Support your local FREEBIRDS MC
1986/5 Vn700/750 Frankenfook cross eyed bitch "Mellisa Fayhe"
I am a BIKER and i'm proud.FREEBIRDS MC CENTRAL NY

lowered with progessive 412 10" shocks
rejetted for K/N Pods part#rc 2340
sportster seat

'I didn't lose my mind.i gave it away

BRING BACK WOLFIE."Peace and Carrots"RIP
"And I'm free...as a bird"John Lennon Free as a Bird
"I only carry when I have my pants on"Joe Robinson RIP aka Old Dog
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post #7 of 175 (permalink) Old 09-25-2015, 10:34 AM Thread Starter
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MTB, I wouldn't have known about the voltage changes without the dash mounted volt meter. Might never would have connected the increase in volts with doing this mod, I also just needed the start button working again.

Thanks for the quick sticky.

Spread the word folks, I think this will help a lot of riders. I'd say it ranks somewhere on the list of things to do when you first bring your Vulcan home, because it could prevent ever having these problems. On the list with checking spline lube, etc. Add to The Verses?

Don't know who might have discovered this bypass first, but I figured it out for myself and as soon as I mentioned it, MTB confirmed it worked for him 1 1/2 years earlier. I then knew to proceed with cutting those wires. Thanks again, MTB.

If anyone sees a mistake in the write-up, or comes up with more info, we'll edit it into the first post as well. Wasn't sure what to call it, JBStarChargVI or JBSCVI (junction box start charge volts ignition) seemed too much, The Two Wire Mod sounds simple, as it is to do.

It's possible this mod might make the ign. coil relay mod obsolete. That yellow/red shorting in the JB, may be responsible for the voltage drop through the yellow/red to the IC and then to the coils. Or the improved voltage on the yellow/red at the IC provides better spark timing adjustment on cranking. I'm just not sure.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf
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post #8 of 175 (permalink) Old 09-25-2015, 10:53 AM
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without having an internal schematic of the ignitor box, there is probably no way we will ever figure out what happens when the start button is pressed. we can speculate due to what we see happening, but thats about it.

almost makes me want an old one to disect and reverse engineer.

2005 VN750

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post #9 of 175 (permalink) Old 09-25-2015, 11:20 AM Thread Starter
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KC2 has repaired some JBs, he may have something to add if he sees this. Haven't seen him for a few weeks though.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf

Last edited by Spockster; 09-25-2015 at 11:54 AM.
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post #10 of 175 (permalink) Old 09-25-2015, 12:22 PM
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Unhappy No Headlight

So I did this mod and now my headlight doesn't come on. No low beam or high beam and no warning lights on the dash. I'm know my light was working yesterday. My bike is stock otherwise, can someone help me?
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