1982 Suzuki GS850L Ignition Woes

[Tofuball]

Hello! I bought this bike a while ago, and it's always had issues. I just rebuilt all four carbs, and the engine itself, AND did the valves (It desperately needed all of those) AND repainted the tank/side covers.

The bike has over 25,500 miles on it.

However, the bike will start and then die, and then refuse to start again. I found that one of the coils was not firing (The 1&4 IIRC). I found that when I jiggle the wiring harness, sometimes the coil would come back online and start firing again. I found a few loose connections, and replaced that section of the harness. In the process I found one of the tabs on the ignition module (the black thing under the battery on the left side of the bike) had broken off (the one closest to the road), so I soldered it back on, hoping that the heat wouldn't fry the module.

Cyls 1 and 4 still do not fire.

Also I have two different kinds of ignition coil on my bike, one is black, one is brown. I can get pictures if you think it would help.

So, here are my questions:

1) How do you test for a bad ignition module?
2) How should I troubleshoot this?
3) Is there an aftermarket product (Such as something Dyna makes) that would replace the entire assembly?
4) Failing that, where can I get another ignition module?

I've put a lot of work into this, and I can see the light at the end of the tunnel, I just have to figure out this last problem, I hope!

Thank you all for reading this, and thanks in advance to all who attempt to help

[1150bob]

I,just today hooked up my new ign module from 'hyper pac' and it runs great, even with the 2 year old gas. I had the same issues you mentioned and by searching this forum found most of the tests for all the ign components. Just google 'wayne gum' and you should get a listing for his Ebay stuff. Shipping time was 17 business days(1 month)

[flyingace]

Seems to me you haven't resolved if the 'bad' coil is getting voltage. Get a multi-tester out, disconnect the coil leads and see of they have 12 V with the ignition on. If it doesn't, forget about the ignition module until you get voltage to the coil.

A lot of folks connect the coil directly to the battery via a relay. I haven't done this because I haven't needed to, but it may be appropriate for you. They have a specific name for it I can't remember, but there's lots of threads on it.

good luck.

[doctorgonzo]

"Coil Relay mod" Very nice, and pretty easy to do.
Though you COULD have a bad coil, or a bad igniter as well. Check the voltage at the coils. If the igniter is bad (there's a test procedure in the manual) DON'T BUY A NEW ONE. They very expensive, get a used one, or an aftermarket system like Dyna. After market coils are available too, but first, make sure it's not just a wiring issue.

[Tofuball]

OK! Step 1, check for 12V with IGN on, if NO, then do the RELAY MOD. Got it! Thanks

Then check coil to see if it's bad, if it is, don't buy new.

Awesome. I'll definitely look into that eBay unit if all the tests return that the ignition module is bad. This unit replaces the ignition module entirely? Awesome. I'll also have to figure out how it differs from the various Dyna setups. So much to look up :P Thank you all for your replies

[flyingace]

Is your name Navin Johnson?

Seriously, you don't necessarily have to do the coil relay mod. You probably just have a grounded or broken wire to the coil. Just trace it back to the source and see where it stops being 'hot'. A wiring diagram helps ID the wire color and where it goes. I think you can get these at Basscliffs site. If the voltage is low, that's more of consideration for the mod, but even then, probably a new wire is all you need.

Like I said, I've gotten by fine without this mod for 3 years. To me, it's just one more thing that can break (as mechanical relays are prone to do). Just IMO guys.

[doctorgonzo]

Is your name Navin Johnson?

Seriously, you don't necessarily have to do the coil relay mod. You probably just have a grounded or broken wire to the coil. Just trace it back to the source and see where it stops being 'hot'. A wiring diagram helps ID the wire color and where it goes. I think you can get these at Basscliffs site. If the voltage is low, that's more of consideration for the mod, but even then, probably a new wire is all you need.

Like I said, I've gotten by fine without this mod for 3 years. To me, it's just one more thing that can break (as mechanical relays are prone to do). Just IMO guys.

No need to do it if you don't have a problem I agree. I have a totally new wiring harness but was still only getting 9 volts to the coils (likely culprit the original kill switch) so for me it made a world of difference.

[flyingace]

I guess it's just me, but I'd want to find out why I was only getting 9 V. at the coils. I mean, something must be broken, weak, worn or something to get that kind of voltage drop. If votage is low at the coils, where else could this drop cause problems. Is the coil mod just a bandaid over a larger problem?

Tofu, I hope this is relevant to you. I don't want to hikack your thread.

[doctorgonzo]

I guess it's just me, but I'd want to find out why I was only getting 9 V. at the coils. I mean, something must be broken, weak, worn or something to get that kind of voltage drop. If votage is low at the coils, where else could this drop cause problems. Is the coil mod just a bandaid over a larger problem?

Tofu, I hope this is relevant to you. I don't want to hikack your thread.

Like I said, likely culprit is the kill switch since that one of the few pieces of original wiring. I'll probably replace it at some point with the (if I remember right) $90 NOS one, but in the meantime this resolved the issue, plus, there is really no downside to the mod. Up to a point (12.5 volts) more volts is always good. Bike will probably run fine at the 11 or so most people with good wiring have, but gonna be a better spark with 12. I have 155 main jets in mine I need all the spark I can get.

[Tofuball]

Nope, Jason :P

I think you can get these at Basscliffs site.

I cannot, there is no 82 850 manual there

Tofu, I hope this is relevant to you. I don't want to hikack your thread.

Totally relevant. I'm going outside to test it right now

[Tofuball]

OK, I tested it at the coils and it's getting a nice healthy +12V!

Then . . . it wasn't! It dropped all the way to +.56V.

So, I cant get it to go back to +12V, just +.56V.

For either coil!

Jiggling the harness changed nothing. I wish I could get my hands on a good wiring diagram, I could just rewire this thing.

Is a new harness affordable?

[flyingace]

Jason,
To test the hot lead properly, you need to ground the negative pole of the multitester lead and put the + lead on the hot wire to the coil. I use the triple clamp to ground. You get low voltage readings like that if you hook up both coil wires to the multitester. if this is already how you did it, just ignore this.

I just read my own coil voltage. An underwhelming 10.32 V.

[Tofuball]

Jason,
To test the hot lead properly, you need to ground the negative pole of the multitester lead and put the + lead on the hot wire to the coil. I use the triple clamp to ground. You get low voltage readings like that if you hook up both coil wires to the multitester. if this is already how you did it, just ignore this.

I just read my own coil voltage. An underwhelming 10.32 V.

Aye, that is what I did. I guess I'll give the coil relay mod a shot, simpler then sorting out what's REALLY wrong I guess (This harness is so shot . . . )

[doctorgonzo]

OK, I tested it at the coils and it's getting a nice healthy +12V!

Then . . . it wasn't! It dropped all the way to +.56V.

So, I cant get it to go back to +12V, just +.56V.

For either coil!

Jiggling the harness changed nothing. I wish I could get my hands on a good wiring diagram, I could just rewire this thing.

Is a new harness affordable?

Not sure if yours is available or not. A new harness for my 1000 was about $150 bucks, very reasonable.

[flyingace]

Maybe the Dr. can confirm or deny this, but to go from 12 V to .56 sounds like a short in the wiring somewhere. This is different than low voltage which is the usual reason for the coil relay. The issue is, the relay may be hooked up to the same wire that is shorting out, and you may find the relay doesn't operate. I think you are going to have to find out where the coil wire is shorting out.