Source for peak voltage adapters?

[KatScratchFever]

This bike is cursed, I swear to god. . .

Had it running last week (albeit too lean). Made some modifications this week and adjusted the mixture and now am getting NO (zip, zero, zilch) spark at any plug. I've done all the resistance tests I can think of on the signal generator, plugs, coils (primary & secondary), etc. per the manual.

The troubleshooting guide says to test for peak voltages at the ignitor box (computer) from the signal generator and from the coils. Anyone know where to find a peak voltage adapter for a multimeter - preferably inexpensive? I can only find one (from Snap-On) which is a multimeter with peak voltage function built in, but it's also $600. And there's a place in England somewhere if I want to wait for two months or however long it takes for it to get here (I don't).

So anyone have a source for this? Or should I just assume the CDI took a schit between last week & this week?

[TheSteve]

I dont think you need to know exactly what the peak voltages are, just as long as you can see there is intermittent voltage. You should see a bit of AC voltage from the signal generator. Are you sure youre getting power to the CDI and coils? I had to clean out my kill switch to get my spark to work.

[KatScratchFever]

Well, it's a bit tricky to see any fluctuations with my particular multimeter (it's digital). I didn't try it on A/C mode, so perhaps I can try that and see if I get anything insofar as a positive reading - that's a good idea.

I did test battery voltage at the CDI between the orange/red and black/white (earth) wires per the diagnostic procedure, so AFAIK everything's fine there.

I'd sure love to know if my signal generator is going bad. Coils are brand spankin' new AND they worked last weekend, so the likelihood they both mysteriously went bad all of a sudden this week is pretty much zero.

Here's my suspicion (bit of a long-winded explanation, so bear with me):

The harness going to the ignition switch under the tank fell apart on me a while back (crappy plastic) so I cut the plastic harness out and replaced it with a bunch of 6" long splice wires (one for each wire that had been in the harness that I cut out). I'm certain that all the splices are fine (tested them for continuity) but wonder if in the course of my working on them if I fried the computer? Is this even possible? I do recall the orange & red wires happened to touch briefly, which made all the lights come on and stuff while I was working on things, but essentially that only does the same thing as when the ignition switch gets turned on (check the switch diagrams - with ignition "ON" it completes the circuit between the orange & red wires) so in theory that shouldn't matter (it was a reminder for me to disconnect the battery though!)

I also have the TPS unplugged at the moment (the resistances were out of spec, so I was going to adjust it per the manual once I got it running). Would having that unplugged kill spark COMPLETELY? I suspect not, but I don't know for sure. . .

I'm strongly thinking I somehow cooked the computer at this point. Dunno what else it could be. Thoughts?

[TheSteve]

Eh thats a last resort. Id say the computer is probably fine, I dont think its as sensitive as one you'd find in a car. The TPS shouldnt kill spark, but I have a pre, so im not sure. I hear it just kills the spark advance. It'll run like ****, but itll run.

[KatScratchFever]

That's my understanding too.

Here's what I've checked as of this morning:

- resistance of primary & secondary coil windings (OK)
- resistance of signal generator (OK)
- voltage at CDI box per manual (OK)
- battery charge (OK, battery is relatively new too)
- Resistance at each wire in harness I've spliced into (OK)
- All fuses (OK)
- Connection of all harnesses (OK)

The only things I've messed with between last week & this week (aside from the carb mixtures) are:

- replaced broken ignition switch harness with wire splices (described above)
- disconnected TPS (adjustment required, described above)
- swapped out headlight switch (old one had failed - separate issue, new one works fine)

Bike is definitely getting fuel when cranked (you can see fuel vapor coming out the tailpipe and the fuel level in my test tank goes down slightly)

Am I missing something simple here? It's mind-blowing since the bike ran last week for initial carb-tuning tests. . .

[TheSteve]

I cant think of anything else. Fouled plugs maybe? If you pull a plug and ground it to the engine do you get a spark at all? What about grounding the plug to the frame?

[KatScratchFever]

Negative. The plugs are pretty new - only about 50 miles on them. And they ran fine last weekend. I tried grounding the plug to the engine case & cranking - no spark on any cylinder. I also tried running a wire from the spark plug threads to the battery negative terminal. No difference - still no spark.

One thing I did notice in my diagnostics:

The ignition switch orange/red and black/white wires do NOT go to zero ohms when the switch is turned to "on". This is not normal. The orange wire & red wire go to 0 ohm, as do the gray & brown. The orange/red and black/white are supposed to but do not. So maybe the ignition switch has gone bad too (?)

I did connect the orange/red wire directly to the black/white wire, effectively taking the "bad" ignition switch out of the loop. Still nothing though. No spark whatsoever.

WTF?

[TheSteve]

Damn dude, sounds like you've checked everything. Is there a spare CDI you could try? Maybe try plugging the TPS back in. Even out of adjustment maybe itll be enough to get a spark. I'm not too sure at this point.

[KatScratchFever]

I have a local m/c junkyard that's got several katanas; I'll swing down there at lunch tomorrow and see if I can buy a new CDI for a semi-reasonable price. Boy, I'd be happy if I plugged it in and "vroom". But I do have to wonder. . . even if it IS the CDI, what caused it to fail? That's my biggest fear - having the root cause not addressed and blowing through multiple (expensive) computers. . .

Yea, I tried plugging the TPS back in too just for yuks. No change there either. Sheesh. When I screw stuff up, I screw it up BAD.