81 GPZ550 Not getting 12v to coils... no spark...

  • PanShovelMike
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11 Aug 2015 12:50 #685417 by PanShovelMike
Trying to get my project '81 GPZ550 running. Finally got the carbs 100% sorted out after rebuilding/cleaning them 3 times, but now I'm not getting spark to any of the plug wires. Checked for 12V at the coil power wires, and each one is only getting .1 volt. This is with key ON, killswitch in RUN position, bike in neutral. Since I'm getting basically no power to the coils, I started testing for voltage with a multimeter along what I believe is the path followed the power wires to the coils:

At the battery terminals - 12V
At the starter solenoid terminals - 12V
2 skinny wires from BATT + (one single barrel, one double barrel) - 12V at all 3 wires, measured after the barrel connectors
Power IN and OUT of the IGNITION SW - 11V (had a 1 volt drop between the batt and ign switch... hmm.. normal? Probably not...)
Power IN and OUT of the KILL SWITCH (right side hand control) - .13V
Power IN and OUT of the CLUTCH LEVER SWITCH - .13V
Power to spade terminal wires at COILS - .1V

I checked for a side-stand switch or wiring, but they do not exist on this bike.

One other thing worth mentioning... the previous owner said the push button starter switch was broken. They had wired a momentary push button onto the starter solenoid itself between the 2 large lugs. On one of the lugs (the one going to the starter itself) there is also a short length of skinny wire with a female barrel connector on it - which is connected to nothing. I cannot figure out what is supposed to plug into it and I'm confused because I'm pretty sure that particular lug only has power going to it while the solenoid is engaged and the starter is spinning... not sure what on the bike would take power from such a momentary source...?

I realize that the batt being at 12V is lower than we'd like and I do have a different (better) batt to swap in. But for the purposes of this test I think a batt at 12V was ok? So... the 1 volt drop in power between the batt and ignition switch is suspicious to me, but it seems the biggest problem comes after the ignition switch. With key on (light position) I get 11V to the various wires leaving the ignition switch. I tested this both before and after the plastic plug thats on the ign switch's little wiring harness. The diagram I was using said the power goes from ign switch to the kill switch, but power coming in to the kill switch is only .13 volt. So does this mean theres a bad wire or connection between the ign switch and kill switch? Can I test this theory by running a jumper wire from an output wire at the ignition switch (where I still get 11 volts) to the PWR IN wire of the kill switch? If I'm thinking right, I should then get voltage passed onto the coils? Any ideas or input that might help me out? Sorry for being long-winded, just trying to describe the issue as best as I can. Thanks very much.

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11 Aug 2015 21:21 #685476 by MFolks
Do you, or can get the shop manual for this bike? You'll need it to sort out what you've got, from what you'll need.
Some places to look for a manual:
Manuals (Some of these websites sell used manuals, just ask)
www.repairmanual.com
www.manualsnmore.com
www.midwestmanuals.com/
www.books4cars.com/
www.repairmanualclub.com/motomanuals/
moto-manuals.com/
www.e-classicbike.com/
www.mediafire.com/

1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)

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