New coils test good. Next step: Ignitor questions

[Anonymous]

I removed the ignitor and there is a small amount of rust corrosion in there. None of the components look overheated. I can't see any heat discolouration on the back of the board. I may just hit some of the suspect-looking joints with my soldering iron and see if that helps, otherwise......

Are there any newer model ignitors that will work with a '81 GS850GL

Is there a simple way to test ignitors that a simple farm boy like me can do?

How much are these things anyway? I've already looked on ebay and found various suzuki ignitors for various prices.

BTW, Thanks Mark for replying about the coil wiring question.

Cheers All

Chris

[IanFrancisco]

From what I can tell from my GS450 factory service manual & wiring diagram, the ignitor is basically a couple of NPN switching transistors that use the small (AC) pulses coming from the signal generator to switch larger amounts of current on and off to the coils at the right time. Not a CDI (capacitor discharge ign.) but transistorized ignition. Not having taken mine apart and looked inside yet I can't offer advice as to how to test it but that's the theory. I think you would have to have a part number for the transistors, specs as to how much voltage they're supposed to put out and a good multimeter before you could do any serious testing. I know the ignitor on my bike ('80 GS450) is the same as on the GS550's from approx. the same time period. I've found them cheap on eBay but it's a crap shoot whether you're getting something useful or just someone else's junk.

[Billy Ricks]

This is for an '85 700 but you can probably use the same tests for your bike.

Remove spark plugs 1 & 2 and ground them to the motor so they will fire when they get power. With the ignitor facing you, the plug on the right side of the ignitor is where the signal generator plug fits. The two terminals on the right side of that portion of the ignitor will be pin 1 at the front and pin 2 at the back. The two left pins will be pin 3 in front and pin 4 at the back. Turn the ignition switch on. With a multitester set a the X1 ohm range put the + probe on pin 2 and the - probe on pin 1. Plug number 1 should fire. Next put the + probe on pin 4 and the - probe on pin 3. Plug number 2 should fire. If this happens the ignitor is good and the signal generators are suspect.

[Anonymous]

Ok, sounds like I can do that test.

I resoldered a few of the suspect joints on the circuit board, and soldered some wire to bypass the suspect corroded track. Took the bike for a spin and it went like a champ.

Cautiously optimistic, the next day I took the bike to work. Got me there, ran like a champ. On the way home however, it began the familiar signs of, no power, throaty sound, surging, seeming like it's only running on two cyls (sort of). Pushed it home after it finally quit entirely

This morning I attacked the ignitor again with my iron and bypassed some more of the suspect circuitboard track.

Didn't fire up like a champ, as it usually does, but on the second attempt it did, and sat there idleling nicely, once it was warmed enough I could push the choke all the way in.

Took it for a run around the block. Ran great for about 1/2 mile then rapidly crapped out. didn't have to push it far this time.

WTF??????

What can go wrong with the signal generator? Does this sound like the ignitor box still?

It's an '81 GS850gl. The (newer) coils are getting full power now, due to my bypass wiring straight from the fuse box. (Complete with inline fuse and a switch so I don't drain the battery while it's parked) Once I get this other problem sorted, I'll go get myself a relay and wire it up properly.

Thanks for all helps and advices.

Chris

[Billy Ricks]

As for testing the signal generators, measure the resistance between the two wires on each pickup. You should get somewhere around 130-200 ohms. If the resistance is infinity or less than spec they are shot.