Is it my ignitor?

[Guest]

Hey guys. New here and haven't gotten a chance to post an intro and pics because I've been wrapped around this spark problem. Have a 1981 GS650L. No spark at 1 and 4. Went over the coils. Swapped the leads from 2 and 3 coil to 1 and 4 and I have spark. Have 4 ohm across the posts but I cant get a read through the boots. Don't know why. The coils work. White spark. Hot. Moved to the pulse generator, which I bought a new one on ebay for 35 bucks installed it still no spark. Later found out how to test across the blue and green wire. Both units, old and new, give me almost 300+ ohms so they are good. Moved on to the igniter. Tried the test jumping the wires, spark plugs out, in boot grounded to head, with the ohmmeter set at multiple settings and no spark on either plug which tells me I'm doing something wrong.
The bike will start fine and run on 2 and 3. I saw a few igniters on ebay ranging from 50 - 700 bucks. WTF? Will a GS850 box work in a 650? Wires look the same but box is different. Im not beyond modifying a mount if it would work. I just don't want to drop a hundred or more on a igniter I don't need.
Any aftermarket boxes work?
Any help is appreciated.

[rustybronco]

What is the resistance measured from plug cap to plug cap on numbers 1 and 4?

Remove the plug caps.

What is the measured resistance from wire to wire (lees plugs caps) on numbers 1 and 4?

[tom203]

After you check plug wire to plug wire resistance ( about 12 Kohms with caps removed). Find the connector that connects the ignition coils to ignitor. This is under seat at top near right frame rail- clean this connector.

nice looking bike- appears well looked after!

[StephenStone]

nice looking bike- appears well looked after!

Thanks...but that's not really my bike but one exactly like it. Mine was well kept too. Didn't have a pic at the time so I grabbed from the web. I cleaned all connectors pretty good already. Did a few resistance tests between multi plug and coil. Seems good. When I get home tonight Ill take some real pics and repost.

[StephenStone]

What is the resistance measured from plug cap to plug cap on numbers 1 and 4?

Remove the plug caps.

What is the measured resistance from wire to wire (lees plugs caps) on numbers 1 and 4?

What should I set the ohmmeter on? I tried this on both coils(good and bad side)and got no reading but the 2 3 coil wire leads when plugged into the 1 4 coil will work. This lead me to believe both coils are good including wires resistors and boots. But I will go over it again when I get home.

[rustybronco]

Any scale above 20,000 Ohms (20K).

[Matchless]

It is most likely your ignitor. Your bike also has the two pickups wired in series, same as the GS850 and 1000. I have recently tested an ignitor from a GS1000 1980 on a GS650 1981 and it worked!
The 1980 type ignitor in the metal enclosure is quite robust and can also be repaired due to the parts not potted compared to the HE module type you have.

[StephenStone]

What is the resistance measured from plug cap to plug cap on numbers 1 and 4?

Remove the plug caps.

What is the measured resistance from wire to wire (lees plugs caps) on numbers 1 and 4?

Ok...I assume this test is with ignition off. With the meter set at 20k The 2/3 side that is good with spark when cranking reads 45.6. The bad side I couldnt get a reading. However...I turned on the ignition and then get a reading same as the other 45.6. Wierd.

[tom203]

If you like your multimeter, don't turn ignition on when you are "ohming "stuff . Remove plug caps from ignition coil, stick probes in plug wires and measure resistance on 20k scale- you'll probably see 12 on your meter which means 12000 ohms.

[StephenStone]

Meter wasn't connected when turned on. Still cant get a real reading. I dont know why its saying 45.6 on the working 2-3 coil.
But Ill repeat this.... If I take the 2-3 coil wires (Black/yellow Orange/white) and plug them into the dead 1-4 side, the coils fires. I bought an ignitor and should have it tomorrow and we will see.
I was going to try switching the blue and green from the signal generator to see if I can get the 1-4 side to fire and rule out a break in the wiring some where. Ive tried both tests with ohmmeter and 1.5 dry cell battery and cant get either side to spark.

[Matchless]

Meter wasn't connected when turned on. Still cant get a real reading. I dont know why its saying 45.6 on the working 2-3 coil.
But Ill repeat this.... If I take the 2-3 coil wires (Black/yellow Orange/white) and plug them into the dead 1-4 side, the coils fires. I bought an ignitor and should have it tomorrow and we will see.
I was going to try switching the blue and green from the signal generator to see if I can get the 1-4 side to fire and rule out a break in the wiring some where. Ive tried both tests with ohmmeter and 1.5 dry cell battery and cant get either side to spark.

Try this step by step:
Remove your ignitor and test it on the bench. The following steps work for the GS1000, but using the bulbs should give very similar results on yours.

1. Find two 12V 10W bulbs (to substitute for your coils) and connect both of the two center prongs of the bulbs to +12V of your test battery.
2. Connect the casing of any one bulb to the Black/Yellow wire and the other bulb to the White wire.
3. Connect the Black/White wire to the battery negative and the Orange/White to the positive +12V of the test battery, preferably through a 1 Amp fuse.
4. The light connected to the White wire will come on immediately when ignitor is powered. The other one is off. This is the rest position and will always be like this on the specific Ignitor for the 1980 models, may differ on other models.
5. Switch on your multimeter, set it to the diode test setting and connect the Black test lead to the Blue wire. Now briefly touch the Red test lead to the Green wire. While you connect it the bulb that was on will go out and the bulb on the Black/Yellow wire will come on. When you remove the connection the bulb will go out and the bulb on the White wire will come on again. You can use a single AA or AAA cell or the lowest resistance test setting on the DMM to do this as well. You are basically just giving the input a negative going pulse as it would have received from the trigger coils.
6. If this works as described your ignitor is in working order.
7. Warning: Do not leave the ignition on for prolonged periods without starting the bike. The coil that is powered could overheat and fail, as well as the driver transistor in the ignitor. With the engine running the ignition and coils are pulsed and thus allows for a cooling off period and the coils are only powered for the dwell duration.

Hope this helps - when testing secondary coil resistance try first with plug caps removed and DMM probes on clean copper of the wires.

[60ratrod]

stephen, i had the exact same issue with my 650g, no spark on 1 & 4. what i had to do to make sure that it was my ignitor was do the test in the service manual. you should pull plugs 1 & 2 and set them on your head in the plug boots, then set your multimeter to the continuity setting and put the negative lead in the green socket and the positive lead in the blue lead. when you do this, #1 should spark, when you remove the positive lead, #2 should spark. if #1 doesn't spark, then your ignitor is toast.

[StephenStone]

stephen, i had the exact same issue with my 650g, no spark on 1 & 4. what i had to do to make sure that it was my ignitor was do the test in the service manual. you should pull plugs 1 & 2 and set them on your head in the plug boots, then set your multimeter to the continuity setting and put the negative lead in the green socket and the positive lead in the blue lead. when you do this, #1 should spark, when you remove the positive lead, #2 should spark. if #1 doesn't spark, then your ignitor is toast.

I tried that test but the manual says use the R1 setting not continuity. Now the R1 setting, I thought, was 20k in the ohmmeter section. Maybe that's why no spark during test from either side blue or green.

[StephenStone]

And how do you remove the boots from the wire? I thought they were crimped on? I did the test with the end caps off and resistors out probing into the threaded hole. Nothin.

[tom203]

And how do you remove the boots from the wire? I thought they were crimped on? I did the test with the end caps off and resistors out probing into the threaded hole. Nothin.

Slide boot back and unscrew cap from coil wire- might need a little pulling at same time. Then stick meter probes into the plug wires and look for about 12000 ohms wire to wire.