03 zx12r number 4 misfiring

[nickjt]

My zx12r was running like shit. Its stock standard, with 14000 k on it. I pointed a temp laser at header pipes, the two inside pipes read the same, number 1 was about 30% down, number 4 was about 50% down....i put a new set of plugs in it, now 1,2 and 3 are the same, but 4 is still down about 50%. I swapped the two outside ( 1 and 4) coil sticks over, and still the fault is at number 4..... the temp laser is still reading about the same on the other three cylinders, and #4 is down about 50% I disconnected the coil stick wiring at that cylinder, and it ran (as you would expect) on three....put it back on, and it runs on three and a half...... So, i don't know if it's a weak spark at that cylinder, or, could it be a fuel problem??? My technical experience is limited to about oil changes and plugs......So, bike is still running like shit.... Can any one give me any ideas as to what this fault could be??? Thanks guys.

[oldman]

I don't have a 12 but all are the same. I would start by checking the compression on all four cylinders. If the compression is ok then your spark plug colour will tell you something. Black plug electrodes means too rich, white and pitted means too lean, a nice tan or light tan all ok. But if it's not the compression it has to be spark or fuel. Good luck. Also Jim Beam enhances the trouble shooting experience. One shot is good 12 is better.

[SteveW]

Use a long screw driver, put it against your injectors and your ear and listen for the clicking noise. If the injector on the dead cylinder makes a very different or no click, it could need replacing.

Also, how old is your battery? Can you borrow another battery and test it out?

See http://kawasakiworld.com/showthread.php?t=10373
Dead Cylinder

[nickjt]

I'm thinking that it probably is actually working, but possibly blocked. Good idea though, will try the screw driver trick....
Battery is just over a year old, and still quite strong.
Thanks.

[nickjt]

Pulled the throttle body out today to check suspect injector.... gave it a good clean out whilst activating the switch on off on off..... reassemble, Arrrrrggghhhh
Still no better!
I noticed while looking down into the ports, that there seemed to be a bit more carbon/gunk build up at the bottom of the valve stems on # 4.
Starting to think it could be valve clearance now????

[oldman]

Starting to think it could be valve clearance now????

Compression check, compression check, compression check....

[nickjt]

Yep, Yep, Yep.....
I reckon so.....
Any ideas on the best way to plumb up a compression tester? or has some one already made the perfect tester for the zx12 and put it on the market, so all i have to do is go buy one???

[oldman]

Any auto parts store will have a compression tester. The question is can it be used on your vehicle? I've found the only thing that works on my Z1000 is the screw in type and it was tricky finding one that would fit under the frame for 2 and 3. I'm sure somebody on this forum that lives somewhat close to you has one. I'm a bit far away or you could use mine. Either disconnect the fuel line or disable your injectors before the test, (you probably have to remove the tank anyway), otherwise the gas will wash the oil off the rings and give you a false, (low) reading. Also the throttle should be open while cranking or you will not have enough air to give you a good reading. It could be your valves are out of adjustment, but if you wait too long the partially open valve will burn and you will have to remove the heads and get a valve job, (kind of like a blow job but a lot less fun and way more expensive). If your only checking 4 maybe you can do it without removing all that shit. Cheers, don't forget the Jim Beam.

[nickjt]

Yeah, other side of the ditch a bit too far....
I went to a hydraulics shop today and got a 3/16ths inch hose (wire reinforced) with a 1/4 bsp male crimped on one end,(to go to pressure guage) the other end i have a 1/4 inch bsp male, that i will take to work (engineering machine shop) along with an old NGKcr9ekpa plug, and weld the two together after getting the ceramic and core out of the plug.....then crimp that end on to the other end of the 3/16ths hose. Hopefully, that should do it.....
Thanks for your help....Will give you an update in a couple of weeks. Busy for the next week or two, so bike will have to wait a while.....
Quite partial to the wild turkey myself.....

[Jonno]

Ok, make sure your battery is in top form these 12's dont like brown power. they need good battery,
once thats sorted then come back.

[oldman]

By the way it may very well not be your compression. It could very well be any of the other things people have suggested. I just don't see beating my head against a wall changing parts and generally fucking the dog without making sure the basic engine is ok, (compression, etc,). No matter how many batteries, spark plugs, fucking wires and coils you replace if you have a dead, (no compressionj) cylinder it is not going to fucking run worth a shit, fucking.

[nickjt]

Compression test is next....
I have now made my compression testing device...the theory behind it is sound, just the practical to put it to the test now.
IF!!!! after my compression test proves that I am down in one lung, (as suspected).... lets say it's not only valve clearance! but, I also have a burnt valve!!!
Can the head on the 12r be removed WITHOUT taking the engine out for a valve job????

[MAXUMIS]

You are best checking the valve clearance before you give it a comp test.A leak down test will tell you all "if it still has the problem.

[oldman]

At your low mileage it is pretty unlikely that you have a valve or cylinder problem. I just like to run the compression check first so I don't, as previously stated, end up doing a whole bunch of shit that costs a lot of money and the problem was low compression for whatever reason.
You can spend a lot of money chasing your tail and no matter what you do if you have low compression it will still run badly. Cheers!

[Zedex 6]

I wouldn't bother with a compression test, as you already know which cylinder is at fault, also compression testing can lead you to lots of bum steers, and do not truly indicate what the cylinder is doing.
as Maxumis mentioned! A cylinder leakage test is the best answer as well a vacuum test on all cylinders.
Going by the pyro readings is No 4 temp taken at idle or above 1500 rpm. Only reason I ask is, readings fluctuate quite a bit at idle and high or low pyro temps can be a little deceiving also. Does the engine smooth out when revving, over and above idle, or does it keep miss-firing.
If it smooths out,
* It's more than likely a valve related issue: Eg. Not seating correctly (worn or cracked valve guide), Hard carboning under the seat (incorrect valve clearance, leaking injector, or worn injector seal, vacuum leak and valve stem oil seal failure or crankcase breather system)
The reason Vacuum and leak down testing will show these faults more so than compression testing or to scope it (Engine ECG)

If it still miss-fires,
*Can be carbon tracking down in the cylinder head (plug bore) where the coil tube connects to the plug and shorting directly to the cylinder head. (look for signs of salting and calcium build a white chalky powder residue in the plug bore or even corrosion around the base of the plug hole) I know you mentioned swapping the coils over, but spark will find its way the least amount of resistance.
*Burnt out valve, Broken valve spring or Sticking valve.
*Vacuum leak, Worn cam lobes

Your carboning can just be the end result of incomplete burn cycles and the unburnt combustion is pulsing back through the intake. I have had Toyota Camry V6's carbon extremely bad due to dirty injetors, and they seam to run, but not well with those issues. Its not until you clean the injectors and de-carbon the manifold the customer really notices the difference(to power and fuel economy)
and Holden Rodeo V6 miss like a bastard when there is simply corrosion down the plug holes.

And I'm with Jonno on this one! I wouldn't overlook the simple battery.............................................It may crank OK, do a full test on it or try a good in your bike first.
I have seen 1st hand at stupid faults, like tripped out Electronic dashes and Miss-fires to even Bikes stalling on decell, only to be able to crank them over, but not re-start.

Good luck in diagnosing, looking forward to what you find.