Misfire on 2 & 3

[Swiss Gaz]

1980 Z1000 LTD B4 (Electronic Ignition) HELP!
Well, I think it is a misfire.... Looking down the trusty color tune you can see it periodically and what can can only be described as "spits" or misfires(?) on idle and only on cyls 2 & 3. Not all the time but enough for a lumpy idle and poor pickup onto the main jet. Bike has never run well since it was imported. Runs great when you open the throttle though with no back fire on the over run. Grin factor 10/10.
Now this to me points to blocked pilot jets given its ONLY on idle. However, you can adjust the screws to get a nice colour where your supposed to find it ie 1 - 1/8th out (or there about and cyls 1 & 4 like this setting). I have taken the carbs off more times than I can mention and tried to clean them out as best I can (high pressure brake cleaner through the pilot chambers and then a good air blow out.
Vacuum for all cylinders is OK.
Balance is OK between all 4.
Tried new 15/17.5/20 # pilot jets. All show same symptom.
Swapped over coils/plugs/leads with Cyl 1 & 4. All parts check good.
Wired George mod done with good 12v to both coils.
Cylinder head off and valves etc all checked.
Bike done less then 5K miles & I have removed all the emissions guff.

Is there anything that I have missed? The electronic ignition is set is it not? Why exactly the same symptoms on 2 & 3 when 1 & 4 run like a doozy and I have proved the coil etc is OK? What else is shared with the two cylinders... IC Igniter? Is there an advance and retard?
I am loathed to fork out to get the the carbs professional cleaned purely because I don't think it will help, I also dont think the carbs are flooding, but what do I know cos i am scratching my head!

Any suggestions folks?

[z1bman]

could be a faulty pick up coil

[KWACKERZ1]

or a broken intermitent poor connection on the pickups for 2+3 to the coil, but the mystery of why at low revs is an puzzle.

[prowlerz1]

All I can suggest is if you have checked everything and everything is correct and the carbs are ok then live with it .. Or.... The only way to make sure it's not the carbs if your not willing to get them sonic cleaned is to put your carbs on another bike see if the symptoms transfer

[warren3200gt]

Surely the fact that it is only low revs points to electrical. When the revs are up you have enough power going through the coil to pump a spark?
A poor earth connection where the lead is soldered to the coil maybe?
I would be checking ALL the electrical connections very carefully on that side of the system and possibly swopping out that coil.
You didn't mention if the fault moved when you swopped the coils. If it didn't then some place between the ignition plate and coil? Have you tried running a separate wire from the ignition to the coil? maybe you have a corroded broken wire in the existing loom?
Just guessing really but it sounds like one of those faults that you need to check every component one by one until it stops.

[z1bman]

normally a fault on no 2&3 would be associated with an electrical fault on the ignition side ? check all electrical connections . on the carb side remove the pilot jets & fill the passageways with 3 in 1 oil & see if there is a difference in the rate that it drains through the carbs. the ones that drain at the slowest rate will give you an indication where to look

[Pigford]

My old favourite.... check +12v at coils & kill switches can be right b*****d's

[z1bman]

guys read the post's properly he has checked the coil voltage swapped the coils & plugs & done the wired George relay mod

[Swiss Gaz]

Thanks for the replies guys. All good stuff. I am going to check all the wiring and see if anything is a miss from the pickup coils and the IC Igniter. As suggested would be good to swap out the carbs but its an expensive check as I dont have any to swap it with. Will report back any findings!

[HowieD]

there are some guides uploaded about voltage drops on electrical connections - hope that helps.

H wie

[Mr Bump]

I'm happy to admit that this is only a suggestion and that lots of chaps here have more expirience than me - but here goes anyway: can you try rotating the cam on the ignition advancer by 180 degrees and swapping the coil low tension wires? This should run shouldn't it? and will then give you a fair clue as to where the fault is e.g if the misfire doesn't move to 1 and 4 it's not the hall sensors on the crank?

Olly

[Pigford]

I'm happy to admit that this is only a suggestion and that lots of chaps here have more expirience than me - but here goes anyway: can you try rotating the cam on the ignition advancer by 180 degrees and swapping the coil low tension wires? This should run shouldn't it? and will then give you a fair clue as to where the fault is e.g if the misfire doesn't move to 1 and 4 it's not the hall sensors on the crank?

Olly

No - the advance unit is keyed at 360 degrees only.

[Mr Bump]

I'm happy to admit that this is only a suggestion and that lots of chaps here have more expirience than me - but here goes anyway: can you try rotating the cam on the ignition advancer by 180 degrees and swapping the coil low tension wires? This should run shouldn't it? and will then give you a fair clue as to where the fault is e.g if the misfire doesn't move to 1 and 4 it's not the hall sensors on the crank?

Olly

No - the advance unit is keyed at 360 degrees only.

Yes, but if it's a Kawasaki mechanical advance (it is on this bike or have I failed to read the thread properly??) you can disengage the actual cam (the bit on the advancer that advances) from the weights and refit it 180 deg out.

I've certainly done it by accident then wondered why my bike won't start....

Olly

[z1bman]

I'm happy to admit that this is only a suggestion and that lots of chaps here have more expirience than me - but here goes anyway: can you try rotating the cam on the ignition advancer by 180 degrees and swapping the coil low tension wires? This should run shouldn't it? and will then give you a fair clue as to where the fault is e.g if the misfire doesn't move to 1 and 4 it's not the hall sensors on the crank?

Olly

i dont think that will work the timing will be 180% out even if you swap the low tension leads on the coils ?

[Swiss Gaz]

Well, I checked all the electrical connections to the coils (these are new by the way) and cut off the old ones and soldered on new ones on. Checked the pickup coils and the mechanical advance. I then convinced myself it was better. Then I convinced myself it was now spitting on all ALL cylinders. I had rigged a sort of IV drip from a bottle so I could run with the tank off with petrol some I use for the mower but soon ran out so I took some from the tank. This I found to have turned into a milky liquid that can only be described as spunky flat lager. It must only be a couple of weeks old.
Hummm.....
I cugged off to the garage to get some fresh in the tank but need to do a longer run to draw in the new stuff. I have seen some posts about petrol so I am wondering if that is my problem or maybe I didnt re-line the tank properly when I did it. I use the local Total garage as I thought they didnt use the bio-ethanol. Thing is it was only filled up a few weeks ago.
Maybe I bite the bullet and save my pocket money for some Dyna coils....