82 GS1100: No spark from coils

[DrImodium]

Project: 82 GS1100 GK

Issue: Not getting spark

Im trying to get a GS1100 to start after a minor overhaul but cant seem to get spark.

I cleaned and jetted the carbs, cleaned up the wiring/terminals, replaced the spark plug wires and end caps, and replaced the R/R with a SH232. It is getting air and fuel, but its not getting spark. Voltage at the coils is 11.05-10.86. Im planning on going and picking up a relay to do the coil relay mod but it should still be putting out some spark, albeit a weak one.

I had an extra set of unknown 77 GS1000 coils (5ohm) and wires and tried swapping them on. My understanding is the 5 Ohm coils work on the 3 ohm system but not the other way around. Even after swapping the coils, I still dont have spark. I could theoretically have 4 dead coils but the 2 that are OEM to the bike were working 6 months ago when It was pulled into the shop.

The bike HAS started ONCE since the overhaul. When It DID start, the RPMs shot straight up and I promptly shut the bike off. Ran for a total of 3 seconds tops.

Battery is on a trickle charger for the night. I have church in the morning but will be working on fixing this issue afterwards.

Suggestions? Need more info?

 

[tom203]

Make sure ignitor is seeing about 12 volts too- your battery sounds low, but you seem like a good candidate for coil relay mod. I'd try a positive jumper wire to orange/white wires at coils and then see if it sparks- if it does, don't forget to disconnect jumper to cut power to coils.

 

[Missile99]

After it started that one time, what did you do? How many times afterward did you try starting it? Is your ignition fuse good and fuse box clean of corrosion?

Are you checking for spark by pulling all the plugs and laying them on the head? If they are old plugs and blackened at all they might be insulated by the buildup and not grounding on the head when testing.

Try what Tom said. The voltage is low. Not sure if it's low enough to prevent spark but possible. Double check your plug wire connections to coils. Check for any wire that you may have bumped while working on stuff.

Hey it started once. I wouldn't think your signal generator or ignitor went bad. Before or after it starts next time back off the idle adjuster so it won't rev so high.

 

[Nessism]

Could be the ignitor, but I'd try the coil relay mod first.

 

[DrImodium]

After it started the one time, It hasnt started again. Ive tried cranking it over at least a dozen times but Im not getting spark.

Whats been replaced so far:

4 new plugs
4 new wires
Coil Relay mod
Stater sol -> bat + (6 gauge)
Motor -> bat - (6 gauge)

Coils are now getting 12v with only .15v lost between the battery and the coils

Havent bench tested the ignitor yet; On the list of things to do today.

Does anyone have ANY suggestions?

 

[Missile99]

Good work on the coil relay, .15v loss is awesome.

Test the signal generator first. It's probably not the cause but it's quick to check resistance. Then try to test the ignitor. If your charging voltage was too high before new R/R this could have caused a failure. The ignitor went bad on mine and I replaced the ignition with a Dyna-S.

 

[DrImodium]

Just hooked up a jumper wire to the coil negative and ground it on the battery negative............GOT A SPARK! Wasnt a very strong one (Battery is at 11.89v right now from testing last night) but at least a spark was produced.

How do you test the signal generator AND the ignitor to find out if they're junk or which one is a fault?

 

[Missile99]

This is what I used:

http://members.dslextreme.com/users/storagecliff/images/electrical_odd-n-ends.html#A11

This is on BassCliff's website.