Misfire issue

[Goatsby]

Just had a clutch cable break 17 miles from home and lost my key in the same day, and now we got misfires! So just after replacing my clutch cable, sometimes under load my bike will hesitate or stumble, and the tachometer will fling wildly all over the place. At first i thought maybe my clutch was slipping, but the actual RPM of the engine doesn't correlate with the jumpy RPM needle. Any ideas?

[Motofool]

Originally Posted by Goatsby

...........just after replacing my clutch cable, sometimes under load my bike will hesitate or stumble, and the tachometer will fling wildly all over the place.......... Any ideas?

It seems that during the replacement of the clutch cable, you inadvertently made an electrical connection intermittently open or discontinue to electricity flow.

What the tachometer really measures is the number of actual sparks per minute.

Now, the production of sparks is erratic.
Check the connectors to both ignition coils as well as the ground connections.
Maybe any wire pinched by the fuel tank?

[Ghostt]

I agree, check the electrics first, if you don't find anything, service the spark plug caps and HT leads.

Write-up available apon request.

[jkv45]

Check your battery voltage. I've seen odd electrical problems because of a battery on the way out.

Also check the wire connector under the tank that goes to the gauges.

[Goatsby]

Thanks guys, will try this.

[Goatsby]

Took the tank off to see if anything was getting pinched or connectors had came loose, but I can't find anything. I'm going to try again I guess. Is this the guide for servicing the spark plug caps? http://faq.ninja250.org/wiki/Cleanin...park_Plug_Caps

[Ghostt]

Yes, also it's my write-up, note the author

Even bad plugs should do something, unless they are totally shot.

Did you renew the HT leads, and disassemble the caps?

Make sure you disassemble the caps, and clean them, and yes the caps get cruddy.

Here my write-up,

Short explanation: The inside of the hard plastic caps accumulate crud the can short out the spark. This can cause rough running or failure to start. Every time you do any work on the bike: remove them disassemble and clean them and renew the wires or at least the connections.

The long Explanation, Warning engineering information can cause Drowsiness.
The ancient cylinder design of the engine dictates that the spark emanate form the center of the combustion chamber. In order to get it there, the plugs had to be located down deep in a well between the cams. This well is a perfect place for dirt and moisture to accumulate. Then because there is no cooling water at this point the metal around the plug runs very hot. Surround this with the large amount of cool metal and you have a recipe for condensation. Now K did drill a drain hole between the fins to help (a little) but it often gets plugged up.

The moisture boils off the base of the plug and the vapor condenses on the cool plastic cap and the plug insulator. This moisture forms a easier path for the electrons to ground than jumping the gap at the plug to make a spark. Misfire.
This issue is right up there with Pilot jets as a cause of trouble.

Here's some pictures that might be helpful. I took these when I replaced the wires themselves, as it was a good time for a write-up, and the wires were OEM from 1998.


Wires are just 7mm copper core, with clear silicone jacket









IMPORTANT NOTICE: make sure to use a proper screwdriver, make sure it fits, as the parts are made of brass inside the spark plug caps

[Goatsby]

Thanks! I'll give it a go.

[Ghostt]

Since the spark plug caps are prone to problems, and the coils themselves are what I consider weak, I've done the Kawasaki ZX Ignition Coil Pack/ coil over plugs (CoPs) modification, not only does it clean up the engine area, but it offers less to go wrong, stronger spark, easily done, and inexpensive.

Something else to consider in the future if your interested.

[Goatsby]

Well, there was a small rubber boot on the right cylinder spark wire, put that back on, and then made 230% sure that everything was nice and attached. Seems okay now. But I think I'm going to switch over to a COP setup. Thanks guys.

[Goatsby]

So the problem started up again, and I serviced the HT leads and caps, to no avail. When it's misfiring in neutral I noticed the neutral light is flickering on and off, would I be correct to assume there is a loose ground causing a short? Do any of you have a picture where the grounds would be for the coil pack? I can't seem to find them. Thanks.

[InvisiBill]

Originally Posted by Goatsby

So the problem started up again, and I serviced the HT leads and caps, to no avail. When it's misfiring in neutral I noticed the neutral light is flickering on and off, would I be correct to assume there is a loose ground causing a short? Do any of you have a picture where the grounds would be for the coil pack? I can't seem to find them. Thanks.

The CDI igniter grounds through the safety switches (clutch, neutral, sidestand). If your neutral light is flickering, you may have a bad connection on the neutral switch, leading the igniter cutting out.

[Goatsby]

I'll have a look, thanks. It didn't start til after I pulled off the clutch cable to have a new one made. I must've budged something loose

[RacinNinja]

Originally Posted by Goatsby

I'll have a look, thanks. It didn't start til after I pulled off the clutch cable to have a new one made. I must've budged something loose

There's a safety switch there on the clutch. Make sure the wires aren't bare or shorting out.

[InvisiBill]

Originally Posted by RacinNinja

There's a safety switch there on the clutch. Make sure the wires aren't bare or shorting out.

Definitely check out the clutch switch (and all safety devices), but this isn't likely to be the cause of the misfire. Problems are usually in the area you last changed something, but it doesn't really fit the symptoms here.

The safety switches are normally open in their "unsafe" positions, and close to ground in the "safe" positions (clutch pulled, in neutral, or sidestand up). If a wire was exposed and shorted against the frame, it would actually force the circuit to "safe" and make it more likely to run when it should shut off. The safety switches seem to have more stuck-open issues, where it comes unplugged or the contacts inside aren't working properly.

And since the switches are normally open, the clutch switch only does something when you're pulling the lever. If it's just sitting there in neutral on the sidestand idling, the clutch switch and sidestand switch aren't doing anything. The neutral switch is providing the ground for the igniter, and for the neutral light, so the flicker hints at a problem with the neutral switch.

The neutral light (along with the other warning lights and gauges) gets power directly from the Ignition fuse on the brown/blue wire. This wire also feeds the igniter, so a power issue there could affect both of those things too.


The starter circuit relay is wired directly to the clutch switch, which is also hooked up to a separate fork off the neutral switch. If there's a problem with the clutch switch, the starter circuit relay can be completely cut off, giving you a dead starter button.

[Motofool]

Originally Posted by Goatsby

I'll have a look, thanks. It didn't start til after I pulled off the clutch cable to have a new one made. I must've budged something loose

Did you remove the clutch lever from the handle bar?

If so, the plunge of the clutch switch may have resulted damaged during re-installation.
It is common to happen:

http://faq.ninja250.org/wiki/Replaci...6_brake_levers

http://faq.ninja250.org/wiki/Checkin..._safety_switch

"If you break off the plunger from the clutch switch, you can take off with the sidestand down, which is of course very dangerous. Don't ride with a broken clutch safety switch."

[Goatsby]

I did not. I took the cable off from the clutch side, the pulled it through under the fairings because I didn't have a key to take the seat off, and needed to have a clutch cable made to have the bike ready in two days as it's my only vehicle. I think I damaged or loosened something when snaking the clutch cable out under the fairings.

[Goatsby]

The issue was resolved after I cleaned everything and renewed the HT leads. How do you guys keep the replacement leads in? Without the little nub on the wire for the caps to screw them into the coil pack, they just press in. Had one of them vibrate itself out on the freeway!

[Ghostt]

For coils just firmly press the HT lead in, it has a pin, not threads, and then tighten the collar, only use your hands, remember its only cheap plastic.
Make sure you have all the parts for the coils installed in the proper order.



For the plug cap, you need to screw them on, the cap has something similar to a self tapping screw inside.



To test just give a tug, they should not come off. If it does try it again, make sure you've trimmed a little off each end, this will assure a good, clean connection.

SIDENOTE: if you planning on keeping awhile personally I'd go with the CoPs modification.

[Goatsby]

Did you cut off the little retaining rubber ring from the original HT leads? Mine seems to be a molded part of the original.

[Ghostt]

Originally Posted by Goatsby

Did you cut off the little retaining rubber ring from the original HT leads? Mine seems to be a molded part of the original.

No, it's needed in order to maintain the seal, it helps keep water out.

It slides off, if your replacing the HT wires you could cut the wire and slide it off, if your not apply some lubricant and then slide it, like getting a ring off a finger.

[Goatsby]

Ah okay, iI'll go look at it. I couldn't get it off because I thought it was molded to the original HT lead. I bought some 7mm copper core and had just pressed them into the colpack and capped it, even though the cap wasn't pushing against anything.

[Ghostt]

Also the plastic ring helps keep the wire in the coil, it works like a ferrule in a pressure fitting, as a matter of fact, it is.


[IMG][/IMG]

[Goatsby]

Yep got it all together, the rubber grommet was glued to the original HT lead, I got them off and it's all good. Hopefully that should keep the leads inside the coilpacks now. Thanks! This forum is always super helpful.

[Ghostt]

Glad to help, just be sure to firmly push, not lightly, the wire into the coil, to be sure it's in completely.

For the reasons of maintenance, issues, weak OEM coils , I've along with others have done the CoPs modification, it's less to go wrong, better spark, easy and inexpensive to do.

I strongly recommend doing the modification/upgrade, as I consider it and update/upgrade, reliability modification, and preventive maintenance.

[InvisiBill]

Originally Posted by Ghostt

Since the spark plug caps are prone to problems, and the coils themselves are what I consider weak, I've done the Kawasaki ZX Ignition Coil Pack/ coil over plugs (CoPs) modification, not only does it clean up the engine area, but it offers less to go wrong, stronger spark, easily done, and inexpensive.

Something else to consider in the future if your interested.

I feel this is a great $25 mod (I did it on my 500 last summer) that cleans up the top of the engine, reduces the number of parts known to have reliability issues, and may even provide a bit more performance. Less stuff in the way, and never have to worry about plug wires again.

[Goatsby]

Well it started back up again, they seem to be making an intermittent connection still. I'm going to do the CoP mod, are the plugs listed in your thread the only ones that work? Can't seem to find them cheap like you guys did.

[InvisiBill]

http://www.ebay.com/itm/162053134920 looks like it only comes with two CoPs, but that's all you need for a single bike anyway...

My understanding is that other modern bikes' stick coils should be very similar and work too, but I had some info on the ZX6R and went with those just to make it easier on myself. http://www.ebay.com/itm/172206068209 should work too (and seems to be in a little better condition).

[Ghostt]

Originally Posted by Goatsby

Well it started back up again, they seem to be making an intermittent connection still. I'm going to do the CoP mod, are the plugs listed in your thread the only ones that work? Can't seem to find them cheap like you guys did.

I run the Iridium plugs, got them from Amazon

NGK (7669) CR8HIX Iridium IX Spark Plug, Pack of 1 https://www.amazon.com/dp/B000HDF852..._uB6oxbJ149777

Just be sure to get NGK, here's more on the subject,

http://faq.ninja250.org/wiki/Changin...rands_to_avoid

Good luck.

[Goatsby]

Thanks, I picked those up. Going to do the conversion when they come in

[Ghostt]

Good deal, hope all goes well, if you need any further information, let me know.

[Goatsby]

I got the new coils in, some of the wiring is different than the one pictued in the guide. Would I be correct to assume it doesn't matter as I'm cutting everything away and only using the two wires into each oem connector?

[InvisiBill]

Originally Posted by Goatsby

I got the new coils in, some of the wiring is different than the one pictued in the guide. Would I be correct to assume it doesn't matter as I'm cutting everything away and only using the two wires into each oem connector?

Yeah, all you're doing is cannibalizing the connector. Here's a pic from another guy who did this on his 500 (using the same '04 ZX6R parts I did, and which you seem to have bought).



That's all you need to do - adapt the harness coil wires to mate up to the plugs on the stick coils. Male spade terminals make it easy and PnP, but you could go so far as to solder them to the harness (since the plug comes off the CoP).

Just hook red to red (positive wire on all cylinders of both bikes) and the other wire to the other color (varies by cylinder).

On the '04 ZX6R, two of the red wires are shorter than the others. I just unwrapped the harness, opened up the crimp on the red wires (to keep them as long as possible), then cut the black wires to match the length of the red ones. You may find that the wires of a certain length work better on your bike (I was able to use one long and one short, so I can keep the other long & short pair together as a set).

[Goatsby]

I electrical taped it together to see if it would work, and it fires right up. I think I have one short and one long per cylinder, will that cause problems? I'm going to solder it to the harness.

[Ghostt]

No doesn't cause any know issues, besides looking bad.

[Goatsby]

So I got it all together, bike starts seems fine...And same issue persists. It's fine getting on and off the throttle, but as soon as i leave it constant it progressively misfires worse and worse.

[Ghostt]

Well it's back to the basics for you then, 're-check all connections, you've missed something, also check the plugs.

[Goatsby]

That's the plan. I replaced them about 2k miles ago when I did the valve clearance but I'm going to do them again.

[Ghostt]

Originally Posted by Goatsby

That's the plan. I replaced them about 2k miles ago when I did the valve clearance but I'm going to do them again.

What brand and part # are the plugs, once you have it all figured out, then you can increase the gap on the plugs to take advantage of the CoPs.

[Goatsby]

NGK CR8HSA are what I picked up last time.