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Discussion Starter · #1 ·
Im trying to bench test a motor? Really just have a issue with the wiring for a bench test I’ve tried but cannot seem to get spark. I have the run switch wired together and I’ve tied the kick stand wires up together. I do have 12 volts at the coils am I missing anything?
 

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1999 Shadow 750 ACE VT750CD3 Modified
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Welcome back. (-:

I don't have schematics for that one, IIRC it's a 1989 VT1100 isn't it?
Just off the top of my head, I'd check the wiring to the ignition boxes and the pulse generators and exciter coil and make sure your grounds are good.
 

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Discussion Starter · #3 ·
Yes sir it’s a 89 vt1100. I checked the coils primary and secondary and pulse generators they checked out good but I’m not sure what the exciter coil is that the static? And is the ignition box the ignition module? And what all needs to be grounded at the coils...my frame has a fresh paint job. Sorry for all the questions lol
 

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1999 Shadow 750 ACE VT750CD3 Modified
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As I said I don't have the schematic for that one or the Service Manual come to that.
The 1100's do vary quite a bit when it comes to the electronics.

The Ignition boxes are the Ignition Control Module, often older bike have one per cylinder, the exciter coil (if it has one) is part of the stator assembly, a wire that is not yelllow and feeds back to the ICM.
I don't know if the coils have to be grounded if you look at the mounting and there is a loop terminal for the bolt then they definitely do.
 

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Discussion Starter · #6 ·
I’ve tried everything I can’t make those thing spark I have voltage at the coils I’m dumb founded
 

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Discussion Starter · #8 ·
I should of took pics but I installed the motor on the bike now hopingaybe it was a ground issue but that didmt work either my old harness is hacked to bits by the previous owner
 

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Discussion Starter · #9 ·
What does it mean when wires at the Low side of the coils all four have 12v and when I turn the bike over they will jump between 12 and 9v on all four wires
 

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1983 Honda vt750 Shadow
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The early systems are like the older points systems. The wires on the coil can have 12 volts on both sides with the key on, till the engine turns and the ignition unit pulse signal controls the ground and then the coil fires. So the variable voltage you see is OK. But the coils should be firing at that time.
Is the ignition unit well grounded with the green wire straight to your test battery?
Black/white or black wires are power to coils and ignition unit.
 

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Discussion Starter · #11 ·
I actually Do not think the green wire is hooked to the test battery. That might be my problem I’ll have to try that when I get home. I wasn’t sure which wire on the ignition module actually went to negative or ground. Thanks for the input!
 

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1983 Honda vt750 Shadow
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Yes green is ground on these bikes.
 

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Discussion Starter · #13 ·
Well I tried the green wire and I think something is off because I have positive 12 volts on the green wire I may need a new harness I dunno... also when I turn off the key the neutral light doesn’t completely turn off the neutral light just becomes really dim I’m stumped
 

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1983 Honda vt750 Shadow
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The green ground may show 12 volts till it is attached to the frame ground or battery, to ground the component where the voltage is coming from.
Just like if you connect a wire from positive to one side of a light bulb socket and the other ground side is left open, you will see 12vots through the filament until you touch it to ground then the bulb lights. Just scratch it to ground and see, but if there is a big spark the wiring is a problem.
 

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A new harness would be one way to go, or you could trace back the wires starting from the battery through the starter solenoid and also up to the ignition switch to your lights and the rat’s nest behind the headlight. If your neutral light is on with the key off, something is cross-wired for sure.
 

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Discussion Starter · #16 ·
Update... i re did the wiring harness and went a head and installed motor hoping for the best. I think I’ve solved all the grounding issues but still no spark. At this point I think it has to be my ignition module. And I’ve looked for one but I cannot find one anywhere so hopefully I’ll be able to find one and a little black box won’t end my project.
 

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Discussion Starter · #19 ·
I think that one maybe it. I can’t find the part number on the one that I have on the bike but it does look like that one. I’m going to take it back off and quadruple check for part numbers before I spend that much on something I want to be sure. Thanks for link!
 

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I think that one maybe it. I can’t find the part number on the one that I have on the bike but it does look like that one. I’m going to take it back off and quadruple check for part numbers before I spend that much on something I want to be sure. Thanks for link!
yep, a lot of money to spend on a guess.
Is there any procedure in the manual for testing the ignition module ?
:D
 
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