Weird...!!!

Hey guys, been a while. Been super busy, but thinkin about all the guys here lol.

So I have an 85 ZX900 Ninja. Weird intermittant spark/revving issue...

New Dyna 2000 + coils.

No change in the condition of the bike ?!?!?!
It still has random missfire on timing light (and audible) EXACTLY like it did before. All 4 plugs.
Still has strange stall out right at mid rpm point, or when twisting the throttle quick - just bogs.

Jetting is set to stock and carbs are perfect. Stock motor.
Compression is in the 140-145 range across all four. No leakdown issues detected... but, burns a little oil in the number four hole - comes and goes. (seemingly unrelated).

I've never really encountered a ghost issue.. lol.

But im about to tear this thing in half...

Any ideas gurus???

Thanks guys, really frustrated

Sounds like a bad or loose connection at one of the safety switches. Eg: clutch safety switch, side stand switch, kill switch.
You can eliminate these one at a time by bypassing each swith. Do them one at a time, and see if that helps.

Well, if you haven't figured it out, it ain't gonna be easy to figure out.

When you put the timing light on the rotor, and there is a misfire, do you see a ghost image of the rotor at some particular angle? Or is it always at some different random location?

When you say "exactly like it did before", do you mean it used to run fine that way, but now it doesn't run fine?

I don't know what the 900 uses for a pickup and rotor, but if it's similar to the electronic-advance KZ models, then:

If the ghost image of the rotor is always in the same place:
There is likely a crosstalk issue in the pickups/rotor, or it can be a vibration in the motor, or play in the crankshaft.

If the pickups are too close to the rotor, that can cause some crosstalk.

If the ghost image of the rotor is always in some random different place:
There may be a bad wire somewhere. It can be a pickup wire has rubbed against the frame somewhere. It can be a coil primary wire is rubbing on a frame somewhere. It can also be something trying to kill the ignition as Vintagebiker mentioned. I've seen flakey neutral switches and flakey kickstand switches cause goofy ignition problems (when they are tied into the ignition as interlocks). The ignition seems fine until you would rev it and the kickstand starts to vibrate, or something in the trans causes the neutral switch to vibrate. For testng, you may want to bypass all of the lockout circuits.

I think a loose pickup assembly could cause the ghost image either way (fixed location or random).
Also, a flakey Dyna 2000 can't be ruled out, unless you had the same problem with the stock igniter.


Sorry, these are just random stabs in the dark. Detecting the pickup signal defects would likely require a scope.

vintagebiker wrote: Sounds like a bad or loose connection at one of the safety switches. Eg: clutch safety switch, side stand switch, kill switch.
You can eliminate these one at a time by bypassing each swith. Do them one at a time, and see if that helps.

Already by-passed these culprits... still same issue.

But thanks!

loudhvx wrote: Well, if you haven't figured it out, it ain't gonna be easy to figure out.

Yeah for sure! lol.

When you put the timing light on the rotor, and there is a misfire, do you see a ghost image of the rotor at some particular angle? Or is it always at some different random location?

By missfire, I mean it just doesnt fire. the timing can be seen to be bang on, but it randomly drops sparks/doesnt fire. always same spot on rotor is seen when it does fire.

When you say "exactly like it did before", do you mean it used to run fine that way, but now it doesn't run fine?

I mean it always ran like this.

I don't know what the 900 uses for a pickup and rotor, but if it's similar to the electronic-advance KZ models, then:

If the ghost image of the rotor is always in the same place:
There is likely a crosstalk issue in the pickups/rotor, or it can be a vibration in the motor, or play in the crankshaft.

If the pickups are too close to the rotor, that can cause some crosstalk.

If the ghost image of the rotor is always in some random different place:
There may be a bad wire somewhere. It can be a pickup wire has rubbed against the frame somewhere. It can be a coil primary wire is rubbing on a frame somewhere. It can also be something trying to kill the ignition as Vintagebiker mentioned. I've seen flakey neutral switches and flakey kickstand switches cause goofy ignition problems (when they are tied into the ignition as interlocks). The ignition seems fine until you would rev it and the kickstand starts to vibrate, or something in the trans causes the neutral switch to vibrate. For testng, you may want to bypass all of the lockout circuits.

I think a loose pickup assembly could cause the ghost image either way (fixed location or random).
Also, a flakey Dyna 2000 can't be ruled out, unless you had the same problem with the stock igniter.

Its all new stuff from Dyna. Rotor magnet, pickups, ignition unit, coils, wires, plugs. The whole ignition is brand new. Timed correctly. Wierding me out :blink:

Its basically doing the exact same thing it was with the old igniter, pickups and coils.

Sorry, these are just random stabs in the dark. Detecting the pickup signal defects would likely require a scope.

Don't applogize, any help is greatly appreciated!

Thanx

I've been doing these things for some time, but admitedly (like any good mechanic lol), i dont pretend to know everything, so I cant rule out maybe there is an actual mechanical problem with the engine causing the spark to go wonky?!?!?

Im not a leak-down expert either, but i know how to "feel" it and slide the piston down to see how things react - no differences on any cylinder... :S

Or am I way off-base?? Could the engine be blowing out the spark - no, not really right, i've only seen that on sick high compression motors... but maybe with oil? blowby?

U know what I mean... mechanical?

:blink: :silly: :pinch:

Do you have access to a scope? If so back probe the pick-up coils and watch the pattern there for starts, then progress through the system hopefully finding the issue. If there is a voltage or ground loss you should be able to pin it down.
Any excessive end play in the crank? Or runout? Put a dial on the end of the crank, check both end play and runout.

Motor Head wrote: Do you have access to a scope? If so back probe the pick-up coils and watch the pattern there for starts, then progress through the system hopefully finding the issue. If there is a voltage or ground loss you should be able to pin it down.
Any excessive end play in the crank? Or runout? Put a dial on the end of the crank, check both end play and runout.

I had a scope but it died good a while a go.

I have run all power and ground connectors straight off a good battery.

How does end-play/runout apply? I mean besides causing clearance or striking issues with the pickups (obviously). I have put a dial on the rotor itself, it has virtually neither.

A brand new Dyna 2000 should just work perfect right out the box. If not, I'll just go buy another of the whole system and swap everything - this troubleshooting crap is costing me time. time = $$$

Meh, oh well - I do like a good mystery, but I also like to ride lol :pinch:

Thanks!

Runout would effect the Airgap sending the signal voltage all over the place. But it sounds like you've checked that. Strange it would be exactly the same between both ignitions, so looking elsewhere seems like it might lead to something. Do you have Min/max on your DVOM? Maybe back probe the pick-ups and check the voltage this way as a good meter will have a high sample rate.

Motor Head wrote: Runout would effect the Airgap sending the signal voltage all over the place. But it sounds like you've checked that. Strange it would be exactly the same between both ignitions, so looking elsewhere seems like it might lead to something. Do you have Min/max on your DVOM? Maybe back probe the pick-ups and check the voltage this way as a good meter will have a high sample rate.

Curious... Even with measurable runout, if the rotor trigered the pickup, then rotated 360degrees, would it not be back in the exact location/amount of runout, and just trigger the pickup again at the same voltage/airgap. OK, so endplay would be the factor here... I think i just answered my own question... :laugh:

Backprobe... sample rate... ugh! LOL I havnt had this much trouble in some time! :side: Dont have a great DVOM - stolen

Yeah! Exact same between both ignition systems! WEEE-ERD!

If not already done, would assure integrity of the ground connection where the negative battery cable attaches to the engine.

And check every connector and fuse clip and switch in the circuitry between the battery positive post and the coil primary terminal.

Good Fortune!

Patton wrote: If not already done, would assure integrity of the ground connection where the negative battery cable attaches to the engine.

And check every connector and fuse clip and switch in the circuitry between the battery positive post and the coil primary terminal.

Good Fortune!

The Dyna 2000 connects directly to the - batt terminal, and I ran a jumper line to the engine case for extra plugs ground.

Jumped the power straight from batt + terminal to both coils and dyna 2000. only temporarily while in use - never left coils connected while not running.

... I only need to turn on the ignition to start the bike, then I can turn it off and watch the bike run all on its own LOL. You can hear the engine and see the spark missing.

Maybe I will post a video tomorrow.

Still puzzled...

:S Thanks all, goodnight.