1982 Suzuki GS1100G Ignition System/ Battery, Coils and Signal Generator Check

[GalDemSuga]

Folks

So while I am awaiting a 2.70 mm valve shim to show up today to complete the top-end, (https://www.thegsresources.com/_for...G-Won-t-Run-Hard-Starts&p=2617611#post2617611) I decided to check the coils for resistance and voltage. On the secondary side I get 33 Kilo-ohms for each coil, which is accomplished by putting a multi-meter lead into each spark plug cap. On the primary side of each coil I get 4.5 ohms which is accomplished by putting the positive lead of the multi-meter onto positive side of the coil and the negative lead of the multi-meter onto the negative side of the coil.

Now the voltage test was not good, I got 11.6 volts on the left coil (orange/white wire) and 10.78 volts on the right coil (orange/white wire) and this was accomplished by putting the positive lead of the multi-meter onto each orange/white wire and the negative lead of the multi-meter onto the engine/frame. The battery is fully charged and measures 12.75 volts. Should I be considering this modification (http://gsarchive.bwringer.com/storagecliff/images/ignition_coil_ relay_part2.pdf)?

Now for the signal generator; Green- Yellow wires are showing 1.26 Mega-ohms and Blue - Black wires are showing 1.66 Mega-ohms. Now page #184 of the Suzuki Manual says that the standard resistance for the signal generator should be 140-200 ohms with the part needing replacement if it shows less than 140-200 ohms or if it shows infinity. I'm assuming the reading of more than 140-200 ohms but less than infinite ohms makes it a good part.

Now for the Igniter Unit; when I follow page #184 of the Suzuki Manual and place plugs 1 and 2 against the engine and connect the multi-meter (set to ohms) to the respective wires (Blue - Yellow plug 1 and Green - Black plug 2) I do not see a spark on plug 1 or on plug 2. I do see a reading of 166.6 ohms in each case. Does this mean that the Igniter Unit is bad?

 

[Gorminrider]

Does the bike run? Do the grounded plugs spark? (keep all plug wires grounded through their plugs when they are "out" of their holes)

otherwise, I would look at a wiring diagram for the bike -the colours you are testing do not agree with mine nevertheless
The diagrams for 1100GL I have here has it that:
Test primary coil resistance across the two connections to the coils(disconnected) that is, where O/W and W and O/W and B/Y connect to coil.

on four cylinder bikes (using a "lost spark") Secondary resistance is checked across the two spark plug leads that connect to each coil, but be aware that OEM spark plug leads contain suppression resistors...but you might have non-oem throughout for all I know... (IF YOU MUST...these come out with a screw driver applied carefully-BEWARE tiny parts- so get a white pillow case or work through a plastic bag wrapped round...a resistance test is not a guarantee that hi-voltage coils are "good" but it does reveal gross faults.

Signal generators- disconnect and test resistance across their leads.

 

[salty_monk]

At those voltages I would definitely be considering the relay mod...

 

[Gorminrider]

I wouldn't. I don't like complications added to a system that, clean and bright, works as is. Especially, a NO relay which I suspect many here use for this mod-I wouldn't trust the relay... among other reasons...
....when a running bike starts, there is no charging going on at that little battery, so VD test across the coils then might inform as to how low the vd can be and still produce a healthy spark....

 

[GalDemSuga]

Does the bike run? Do the grounded plugs spark? (keep all plug wires grounded through their plugs when they are "out" of their holes)

otherwise, I would look at a wiring diagram for the bike -the colours you are testing do not agree with mine nevertheless
The diagrams for 1100GL I have here has it that:
Test primary coil resistance across the two connections to the coils(disconnected) that is, where O/W and W and O/W and B/Y connect to coil.

on four cylinder bikes (using a "lost spark") Secondary resistance is checked across the two spark plug leads that connect to each coil, but be aware that OEM spark plug leads contain suppression resistors...but you might have non-oem throughout for all I know... (IF YOU MUST...these come out with a screw driver applied carefully-BEWARE tiny parts- so get a white pillow case or work through a plastic bag wrapped round...a resistance test is not a guarantee that hi-voltage coils are "good" but it does reveal gross faults.

Signal generators- disconnect and test resistance across their leads.

Although I was skeptical of the Igniter Box as I could not get a test on it as per the Suzuki Manual, the bike started almost effortlessly. It's now in non-running status as I need to redo Carbs. It sparked on all plugs and each cylinder ignited. I was impressed with the sound (sounded like a F1 Car) and throttle response after I got it to idle off Choke. Once these Carbs are back on and I start it again, I will check to see how hot each cylinder is at the exhaust pipes.

 

[Gorminrider]

Then it's best not to puzzle over it until you know more or need to. It's a solid-state device and the guts are a lot of tiny doofunnies soldered together and sealed up. Usually very reliable if you keep your electrical system (including batttery and charging) up to snuff. But FYI, what it does, is to tell your coils when to spark when the little magnets on the crank pass by the signal coils.