No Spark on 93 B4

[DrBandit]

I've searched and searched, got some good reports, but nothing that fits my problem.

I've had this B4 for a few years now. At first she was starting within seconds of turning the motor, then after a year or so it took longer and longer to start. Tore it down gave it a valve job, cleaned the carbs, etc...all actually looked very good.

Then it REALLY started to fail. It would take almost the entire battery of cranking before it would start. Then, nothing. No start. I started looking into the electrical and what-do-you-know...no spark.

I've tested everything! I have 2 pick-up coils, both swapped and tested fine...still no spark.
I got 2 CDI boxes, can't really test them, but to no avail, neither will get it started.
I've tested the coils, they're fine.
I've tested the side-stand relay, it works.At least it tests OK.
The side stand switch works, the clutch switch works, the neutral switch works...I can tell by the dash light and/or the starter won't turn over. So I conclude it's not those.
I did find the little side stand interlock system's diode didn't test right, supposed to have continuity, didn't quite get total continuity, but damn close. I have one ordered....could THAT be it?!?!?!

Any other ideas?
I'm at a loss, pretty frustrated, about to part out this beast.

[olsonm3915]

All of the sidestand, neutral switch, etc. can be ruled out quickly if you probe the +12V supply connection WITH A TEST LIGHT at the igniter, which is marked "OW" and "HA01" on the wiring diagram, presumably Orange/White wire.  Note- don't use a voltmeter, use a test light, to make sure you don't have a high-resistance connection.  If you have +12V at the coils (also verified with a test light, not only a voltmeter) and all the other connections and components are OK you should have a spark.

[DrBandit]

Will do. Thanks for the input.
Do you think the diode could be the culprit? I can't fathom it....but I've seen weirder stuff happen.

[olsonm3915]

If the starter is engaging then the diode(s) are working OK.  You just have to look at the schematic to see that the starter relay cannot be energized if the sidestand relay is not turning on.  If the sidestand relay is turning on, the Igniter should have power, because the same path that supplies power to the starter relay supplies the igniter.

But the first thing to do is verify the presence of +12V at the coils and the igniter, then make sure all the other circuits  to the igniter are complete. 

Make sure the ground wire to the igniter is making a good connection to the negative battery post. 
Make sure there is continuity from the pickup coil at the igniter connector (with the igniter disconnected of course).
Since you aren't getting spark on either coil it's PROBABLY not the primary circuits to the coils but I would check them too.
99% of the time electrical problems are related to connectors (corrosion) or switches (breakage).  Sometimes it is a failure internal to a module like the igniter, but surprisingly this is not the most common failure mode.  Anything that moves is subject to wear.  Anything electrical that is exposed to the elements is subject to corrosion.

[DrBandit]

Thanks Olsonm.
I'll check it all out tonight. Report back tomorrow.

[DrBandit]

Well, it started.
God knows why.
I did what you guys said. No spark.
Started checking out ALL the electrical connection, hitting them with no-ox. No spark.
Got 12vdc everywhere I'm supposed to. The right Ohms everywhere too. No spark.
Out of total frustration I started swapping parts again, pick-up, cdi. Re-checking everything. Even found an unconnected wire (Green/Yellow tracer) that doesn't have a mate.
Then I even put another spark plug (from my wife's Subaru) just to see if I had ruined all 4 plugs. I got one spark out of countless cranks. A glimmer of hope. Put the correct plug into the cable, countless cranks, one spark. At this point I did nothing to the bike...but then I got another spark, then another, then it was continous.
I hurredly put the plug into the motor and rigged up a fuel line from a funnel and low-and-behold...she started!

The only thing I did at the end was take a big gulp of my tequila and tonic out of frustration and she started! Imagine that, my Bandit must like tequila? Finicky bitch!

Tomorrow I'll put it all back together, dawn the leathers and take her out.

I've worked on countless bikes and cars...but this one got me good. Damn. I'm going to pour another cocktail, maybe it'll make her faster....

[Wudy]

At least you didn't have something go on yours that doesn't exist on 90% of other bikes, oh the fun!

Glad you got it sorted (or, rather it sorted itself!).

[DrBandit]

....but there is still that one wire that doesn't seem to go anywhere.....

[camarobandito]

Hello DrBandit,

I had the same problem on my bike when I was doing my carb setup. I had 12 volts everywhere I was supposed to, it would crank over and not start. Though it had to do with the little modification but I wasn't getting spark.

Went through all of the testing and everything was fine. Then I charged the battery, put it in the bike and it got a bit LOUD in my garage!

Next day no start, but it would crank over.I Bought a new battery and all was well.The other one had some defect. It just didn't have enough juice to fire but would crank just fine.

[DrBandit]

CamaroBandito-
Yep. A guy on Thumper Talk (a motocross forum in frequent) had your exact same problem with a GSXR. Finicky thing would only start on a really good or brand new battery. A suspicious ignition design I must regret. It seems to sponge up a lot of power, or needs a lot of power to energize it.

I gotta admit theres more wires on this bike than any other bike I have ever worked on. It's friggin spaghetti in there!

interlocks, side stand switches, relays, diodes, jeeezuuuuzzzzz....

Personally I'd like to pull all the crap off this bike and make the whole ignition system a lot simpler. I may just do that in spite of it. The only thing stopping me is that little black box under the seat...

[olsonm3915]

Personally I'd like to pull all the crap off this bike and make the whole ignition system a lot simpler. I may just do that in spite of it. The only thing stopping me is that little black box under the seat...

What's stopping you?  The igniter only needs +12V, +12V return ("ground"),  the two wires to the pickup coil and a wire to each of the ignition coils.  That's it.  All the supposed complexity you mention is there simply to interface the sidestand switch and the neutral switch.  You absolutely do not need the sidestand relay or the diodes if you don't care about the sidestand and the neutral light interfacing to the igniter.

You could run the whole ignition system off a simple toggle switch if that floats your boat.  But it probably would be nice to keep the kill switch and the ignition switch.  In my opinion the present system is stone simple compared to a fuel injected bike like my FJR.

[DrBandit]

Olsonm-
I like the way you think!

[Chris H]

HI, Good to hear that its running.
Where's the green/yelow wire on ya bike?

Chris.

[DrBandit]

HI, Good to hear that its running.
Where's the green/yelow wire on ya bike?

Chris.

Under the seat. In the big bundle behind the rectifier. The schematic shows that color combo (green/yellow tracer) going to a light on the dash, but all my lights work fine and the 'other' green/yellow, when disconnected turns a light out...and this unmated wire, as checked with a test-light, shows very little voltage (dim light). I never took the time to see what the actual voltage is, especially after the motor started running. Kinda like leave laying dogs lie.

This unmated wire has a bullet end on it, like it was supposed to attached to a female connector...but no unattached female connector anywhere..? I wonder if the previous owner took something off the bike?

I plan to tape it off so no grounding would occur. Makes me think if that was the problem; a grounding of this wire which depleted the power just enough to cause the problem.

[Chris H]

Take a read and see if you got this.
http://forums.banditalley.net/index.php?topic=11897.0

Chris.