Cold Cylinders - 1 and 4

[Hummer]

It's been awhile, so I'm not sure my sig shows it, but I'm on a 1980 GS1000 GLT.

Right off, I'm guessing it's a coil problem

Rebuilt the carbs, cleaned up the engine and the whole bike last year, but still had problems with fueling. Just pulled it out of storage, checked the bowls - no excess fuel - checked the plugs (couldn't remember how they were left in the fall) - looked just perfect; started her up and noticed that #1 and #4 were cold at the exhaust.

Checked the plug on #4 - good spark. Checked #1 - no spark. Switched up the plugs to rule out the wires, and no spark on #1 or #4. Couldn't find a spark no matter how I tried it for about 10 minutes. Then all of a sudden, spark again on #4, but nothing on #1.

Aside from the obvious haunted bike theory, what am I missing here? If it really is a coil problem, what should I be looking at as replacements?

Thanks!

[BassCliff]

Hi,

Igniter/Signal Generator/Coil Test
Igniter Repair/Testing (2MB PDF)
Testing The Ignition System

Sorry, it's late and I don't feel like typing a lot. Are you getting 12 volts at both coils? Have you replaced the spark plug caps?


Thank you for your indulgence,

BassCliff

[Hummer]

Thanks for the quick reply...unfortunately drywall, tape and mud became my priority over the weekend, which disappeared far too fast!

I was able to run a few tests late this evening. The guides you posted have been a great help...I'm getting just a touch below 12v at the coil. However, when measuring the ignition coil resistance as per the guidelines, one coil falls within spec (30-35 K ohm), but the other shoots to somewhere around 170 K ohm...now either I'm doing something funky or that's my answer right there. I work on electronics so intermittently that I'm not confident with any result, but that also just happens to be the coil firing 1 and 4, which takes me back to my preliminary guesstimate.

Thoughts?

[chef1366]

Swap the coil wires and see if the problem follows to the two and three.
Don't swap the O/W wire just the other two.

[Hummer]

Swapping wires is a little difficult...I understand there are a few different versions of the factory coils and mine just happen to be the ones with soldered connections buried under some sort of factory goop. Everything is sealed up.

[chef1366]

Swapping wires is a little difficult...I understand there are a few different versions of the factory coils and mine just happen to be the ones with soldered connections buried under some sort of factory goop. Everything is sealed up.

Not the spark plug leads but the actual connections to the harness.

[Hummer]

I'll take a look when I get back to the garage in a few hours. Just to be clear, you're saying disconnect the coil from the main harness via the plastic connector and swap right for left?

I'm sitting in an office right now so everything is based on memory, but humour me for a second since I should be working instead of attempting to mentally chase the ghosts from my machine....

Following the links BassCliff posted, everything checked out until I got to testing coil resistance, which was done by looking at each coil individually as follows: with coil disconnected from the harness altogether, negative probe from multimeter on one spark plug lead, postive probe on the other spark plug lead, compare values. That's where my inconsistent readout of 30 K ohm versus 170 K ohm came into play...they should both be around 30 K ohm, right?

[BigD_83]

I'll take a look when I get back to the garage in a few hours. Just to be clear, you're saying disconnect the coil from the main harness via the plastic connector and swap right for left?

I'm sitting in an office right now so everything is based on memory, but humour me for a second since I should be working instead of attempting to mentally chase the ghosts from my machine....

Following the links BassCliff posted, everything checked out until I got to testing coil resistance, which was done by looking at each coil individually as follows: with coil disconnected from the harness altogether, negative probe from multimeter on one spark plug lead, postive probe on the other spark plug lead, compare values. That's where my inconsistent readout of 30 K ohm versus 170 K ohm came into play...they should both be around 30 K ohm, right?

Yup, depending on your spark plug cap resistance, they should be in the 25 - 35kOhm range. Once you swap the wires around, and the problem follows, detach the plug caps and check the resistance of the ones on the coils giving you issues. This is a known, and pretty common failure point

[Hummer]

I didn't trust my memory at work this afternoon, but confirmed this evening that the connectors coming off the coils are idiot-proof...meaning that one is male, one female where the connection is made to the wiring harness. That being the case, there's no easy cross wiring to test the functionality.

So after spending the whole summer last year cleaning up this bike as a present to my dad (which started as a carb rebuild and quickly progressed into a "down the frame" paint, cleanup and overhaul), I'm perfectly happy to spend a little money instead of fixing something I thought I had dealt with last year.

Can anyone point me in the right direction for new coils? I'm in the process of learning a new career, have limited time, and it appears that although I read everything I could on this site, BassCliff's site, service manuals and all, anything I learned has been replaced with...well, I'm not sure what.

I see Z1 has several choices. I'm looking for simple and straightforward. What's the bolt on replacement for the factory parts?

Thanks!

[BigD_83]

I think you are getting a little mixed up with the directions. What is being said is swap the two female connections from the coils themselves. One should be black, and the other coil wire should be white. The O/W wires do not need to be switched.

Just because it seems like the coils are not working doesn't mean they are the problem. It could also be the signal generator. You should test everything out because the coil option is not inexpensive

As for bolt-on replacements...it'll either be the DC 1-1 (3 Ohm greens) or the DC 8-1 (5 Ohm blacks). I wouldn't say it is a direct plug and play, though. You'll have to do some mount changes, and a little wiring. Each set of two is $130, and you'll need plug wires, $17.00). I believe that most people have gone with the green coils.

You could also get a stock coil set from Boulevard Suzuki for about $110.

http://www.boulevardsuzuki.com/fiche_section_detail.asp?section=95750&category=Motorcycles&make=SUZUKI&year=1980&fveh=2152

You can get the plug caps cheaper elsewhere.

[BigD_83]

...and you can call Jeff at Z1. He's super helpful

[Hummer]

You're right - I should go through all the tests here no matter what. I was thinking it couldn't hurt to upgrade the coils regardless of what I find, considering they're originals, but I've been scouring the message boards all evening and the bug is biting again - I'm going to start tearing into the bike again when I should be enjoying it this time of year!

As far as the misdirection, I think I've been a little murky in my description.

Left coil has the positive wire soldered and epoxied on one end, negative soldered and epoxied on the other end, and both run to the wiring harness where the female connector on the coil side plugs into the male connector on the harness side.

Right coil has the positive wire soldered and epoxied on one end, negative soldered and epoxied on the other end, and both run to the wiring harness where the male connector on the coil side plugs into the female connector on the harness side.

Both coils have the spark plug wires epoxied into the coil body.

I guess I could jumper the connectors male to male and female to female, but I also think that as long as I'm thorough, there really won't be a need. I can remove the plug caps and test the resistance through the wires to rule them out and continue with the tests as per the guidelines.

A whole new electronic ignition sure looks good though...

[Hummer]

Daydreaming in the office again...is the $500ish Dyna Electronic kit on Z1 worth it? I can justify the $130 for new coils...looks like I'd need the black 5 ohm set, new wires and caps are easy/cheap enough...but why not go all the way with the upgrade? Talk me in or out of it!

[BigD_83]

That's the Dyna 2000 you're looking at? Maybe Trevor would sell you the one he just got with his 1100.

Would be a bit rich for my restomod. A Dyna S with coils would be 1/2 the price, and unless $250 is pocket change for you, can be sunk into other performance areas of the bike (thinking new shocks or fork springs)

[Hummer]

Ignition is an area of the bike I haven't tackled yet so I'm not familiar with the Dyna line...when I searched Z1 that seemd to be the only option that popped up for a full ignition. I'll save money anywhere I can! I thought that the programmable system might be a little much...

Where can I find the Dyna S? You're halfway to convincing me this is the way to go...you just saved me $250...haha