Z900 A4 not running right on 2 cylinders

[Gray17]

Morning Guys, its been a while, thats because i re stripped the kawasaki down again, replaced the cam chain as Rob recomended, had Carburettors stripped and ultrasonically cleaned all new genuine Mikuni internals, new rubber fuel lines (this was one of the issues, wrong rubber prev used), new clutch plates , pivot rod, ball bearing etc.
All new gaskets a 2nd time. Tank re sprayed after disaster with E5 fuel blistering it. Looks mint!
So finally assembled everything, replaced oil and filter, connected up the battery, it fired up on choke immediately but 2 outer cylinders run perfect, 2 inners not so, the exhausts outers hot, inners luke warm only? Carbs all full of fuel checked with drain screws, sparks on all 4 plugs.
So im stumped, suggestions please.
Thanks

[gray]

2 inner cylinders - I'm thinking the coil that feeds those 2 cylinders as a starting point to look at. Are you on electronic or points ignition? If points, then the points ( gap, points surface and timing) or the condenser that feeds those 2 cylinders might be the next thing to check

[zed9]

Try swopping cylinders 2 and 3 spark plug caps over you might have them wrong way round. One coil supplies cylinders 1 and 4 the other 2 and 3.

[zed1015]

Try swopping cylinders 2 and 3 spark plug caps over you might have them wrong way round.

Swapping caps won't make a difference.
Both 2 and 3 fire simultaneously with alternating wasted sparks.
It does sound like an issue related to that coil though.

[Gray17]

Appreciate the replies Guys
In answer to question's yes its on electronic ignition, i did have a problem with the pick up magnet falling out but thats now resolved, ign timing is still spot on and the advance and retard free and working as it should. The bike also has the relay mod which ensures full batt voltage present at both coils. However i have disconnected this and tried without, but no difference.
Plugs have been removed and were both wet but not sooty, both 2 and 3 have good fat spark when held against cylinder head and engine spun over.
Theres great compression from those 2 cylinders too as there should be as engines had full rebore and new pistons etc.under tank wiring has been checked seems ok.
My next step as suggested would be to swop coils over and see if problem moves to cylinders 1 and 4 in which case its prob a dicky coil, or the pick up on that coil.
Thanks

[zed1015]

If it's still got that Chinese ignition i'd get a proper Dyna 'S' fitted instead.

[gray]

I tried the Wired george mod to give the coils full voltage and it melted them., 1 after the other. If you have a multimeter compare the resistances and continuities between the 2 coils - you should be able to do this without removing them. 1 of the coils might be on the way out, and reversing the mod won't make it better.

[gray]

to clarify - resistances and continuities in each coil, and compare the readings between the 2 coils

[Gray17]

Thanks for replies.
First off ill check the coils as suggested on ohms to compare between the 2, but if i swop over the coils then surely fault will swop to cylinders 1 and 4 and cylinders 2 and 3 should run ok
Ill also check the ignition pickups again these can be swopped over as their identical. If ones failed then next step is replacement ignition, or refit original points and condensers back again.
Least ive now got things to try to establish whats causing it.
Will keep you all posted
Thanks

[Mally]

Are you still running with the original wiring harness? I have changed mine out to a zPower replica as I was getting a few faults that I am putting down to high resistance and poor earths.

I guess also you don't have the original Ballast Resistor fitted and the coils are new 5 ohm ( not 3 ohm ) although with Dyna ignition you can run 3 ohm coils without the ballast resistor, not sure about what your setup is ok with.

I am guessing the wiring from your electronic ignition unit will be new but usually plugs into the harness before it gets to the coils, for a z900 that would be the Green and the Black wires just above the right hand side panel running from under the tank.

The Red/Yellow LT live is common to both coils so I would think that is ok, but would prove the wiring to each coil from the double spade connector is good (Or swap them over to test) .

I would suggest maybe prove the continuity of the Red/Yellows and the Green wire and the Black wire. Also the continuity of all the wiring to your electronic ignition.

I had the Wired George relay setup but to be honest it really didn't make a difference and was just another point for a fault to occur so had removed it.

However to mimic that and if your are happy enough to do so , you could temporarily take a FUSED feed from the battery and connect to the individual Red/Yellows going to each coil, and a direct connection from your electronic ignition "Green and Black" wires to each coil to negate any harness wiring issue. I guess your electronic ignition would have a +ve supply to it also, again I would wire that direct, via an appropriate FUSED supply .

I have Dyna fitted to mine , attached diagram to give an idea how it wires into the harness. Hope it helps.

[Gray17]

Thanks for reply, the george mod was fitted on recomendation from a forum member a year or so ago now. Seemed like a good idea! However i have made it so it can be disconnected easily using the male and female bullet connectors.
Yes i understand the circuits needed and will modify the existing wiring to try it out, basically you are eliminating any loom issues.
My cutoff switch assembly is a new Zpower one and is common feed to the Geaorge mod coil, however as both 1 and 4 and 2 and 3 share a common feed to both via the relay, the fact that 1 and 4 runs fine suggests its something unique to the other coil. So it may well be on its way out, however swopping them over should see the fault change to the other 2 cylinders. Obv something is now causing the issue, it was running ok before the last strip down, apart from the carbs clogging with incorrect rubber feed hose, which has been stripped and cleaned and E5/10 rubber fitted. So this is yet another new issue.

[moizeau]

Have a read through this, Written by Guy (Wookis58 on KZR)
He has given me permission to post it previously

Fundamental Electrical Principles and Fault Diagnosis (V2).pdf

(1.29 MiB) Downloaded 14 times

[gray]

we await with interest your application of logic and stepwise exclusion of possibilities - it's what we all try to do.

[Mally]

Thanks for the reply , apology for keeping it basic , you understand the wiring , bin the relay until it runs properly, agree like others ( and yourself) the coils as a starting point .

[Gray17]

Hi Guys, thanks for all the replies.
So 1st off i disconnected both coils amd measured their resistance both were 4ohm. Next re checked all connections, again ok, then checked voltage at coils both had exactly the same at 12.5v however this rose to 13 8v once bike started.
My friend then came round, he has a decent set of 4 gauges and remote fuel tank set up. We fitted it to bike and the carbs were way off balance. Removed carb tops and adjusted all 4 carbs to balance them. The difference in pickup was a lot better but most of all the bike was ticking over better and also all 4 now getting to similar temp on exhausts, inside 2 slightly less hot then outer 2?. Havn't been for a ride on it as yet as too damp, but hoping thats cured the issue.