How to measure voltage going to coils?

I see there is two wires that connect to the coil. Once is green, and one is red. I assume that the green is the ground, and the red is positive. I get around 6-8 vdc on one coil, and about 10 vdc on the other side. Did I measure the voltage correctly?

If I recall correctly, turn on the kill switch and ignition then ground the black electrode on the engine case and place the red probe on the "tang" on the front of the coil, repeat for both sides. Make sure your on VDC.

A good idea to measure the V accross the battery with everything off. Fist test the potential of the battery. IE. your coil test will be meaningless if your battery doesn't show 12.X V or so.

With ignition switch ON and kill switch RUN, try touching voltmeter's red probe to coil's red and voltmeter's black probe to engine head.

Good Luck!

check your battery voltage first because that is what you should be getting at the coils and like patton said check between your hot wire and a good engine ground

If you want to measure the absolute voltage across the Coil input with respect to ground/chassis then do as suggested above.

Alternatively, IMHO if you want to measure the loss/voltage drop in the wiring between the battery and the coil input then place the meter Red lead (+) on the Battery Positive (+) and place the Black lead (-) on the Coil input. This is the method you would use to check for bad/high resistance wiring or bad/high resistance connector contacts. Anything over say 0.1 V could be considered suspect and for a connector could be considered a hotspot/heat source. The solution for this type of symptom is wire repair, wire replacement, connector cleaning and or connector replacement. If this solution does give the required results consider the WG Coil Repowering Modification. See here for how I did mine.

This method can also be adapted to measure loss/voltage drop in the wiring between the Engine and the Battery Negative (-).

Hope this helps.

Best of success.
Bill

My battery reads 11.8 dcv.....

Ok, with the key turned to on and the switch set to run, and with the red lead from the multimeter on the red wire that goes to the coil and the black lead on the engine case..

My multimeter reads 11.30 dcv on both coils.

Seems to be a slight voltage loss it seems. Is that okay? I checked both fuse boxes and all fuses are good.

Oh, and I trickle charged the battery like a week and a half ago and it was reading around 12.6 volts I believe. The bike isn't running right now though as the carbs are still off, but I'm wondering if this battery is suspect...because it's not like I've been leaving the lights on the bike or anything.

With battery fluids at correct levels, could charge overnight, then perform specific gravity check (the little floating balls tester), and also have it load tested.

If the battery passes those tests, it's likely okay.

Good Luck!

in colder weather a battery can lose up to a volt a week so the fact it dropped abit would be no real concern if you dont have a load tester you can also hook up the volt meter to the battery then crank the starter over check your reading as your cranking it over if the voltage drops below around 9 volts you might want to look at replacing it make sure the battery is fully charged first before you do this of course.

In review of this crappy wiring diagram, sorry but all I have I think you're looking at this wrong....

The red is the common switched +12Vdc via the emergency stop switch feed into the igniter...

Coil 1/4 has another black conductor from the igniter.
Coil 2/3 has another Green conductor from the igniter
Based on the wiring, these two conductors will be switched rapidly for energizing the coils that feed the spark plugs...

If this holds true then with your DVM set at 20Vdc or auto ranging modes of operations.... Black probe to grounded frame or battery (-) lug (Note, they should be the same)....

Insure your frame/engine is at the same potential as your Battery (-)....

Then place RED probe on this RED conductor.... If all switch assemblies are conducting ideally, this voltage should match +/- .1Vdc of your battery voltage...

Just my observations so may be wrong here...

OMR

To help clarify ---

[Click on image to enlarge view]



Good Luck!