Z1OwnersClub GB

This is really starting to drive me crazy now!
Z1000 MKII - very low mileage motor - only 4,900 miles genuine.
Bike will not pull cleanly until it's above 2000 rpm.
Cylinder 1 plug is sooty all the others are fine.
Here's what I've done to try & solve the problem.
New Plugs.
Carbs stripped & cleaned about 4 times - all the following renewed, pilot jets, Main jets, Needle valves & seats, all o-rings replaced.
Choke plungers are all free.
Service Fuel level checked & adjusted 2 times.
Inlet rubbers removed , checked & resealed at head.
Carbs balanced.
Valve clearances checked & adjusted.
Anyone experienced a similar problem?

Forgot to say:
Engine idles nicely & pulls nicely from 2000 rpm up!

HT lead

If it will reach, try swapping 1 & 4 and see if the problem moves to No.4

could be HT lead or plug cap have you checked the compression?

Make sure you have =12v at coils when running....
Also, carb manifold rubbers

Hi Couple of things to try,are the seals on the bottom of the choke plungers
in good shape? have you checked the pilot air inlet is clear from the air inlet intake on the sooty plug cylinder,as its under 2000rpm suspect its the pilot circuit its not no1 cylinder by any chance? the left one as you sit on the bike.has bike been left standing on side stand?if it has its common for that carb to get gummed up internally,a gunson colourtune is always a good start to check your mixture.....Good luck Paul J

PAULJAC47 wrote:Hi Couple of things to try,are the seals on the bottom of the choke plungers
in good shape? have you checked the pilot air inlet is clear from the air inlet intake on the sooty plug cylinder,as its under 2000rpm suspect its the pilot circuit its not no1 cylinder by any chance? the left one as you sit on the bike.has bike been left standing on side stand?if it has its common for that carb to get gummed up internally,a gunson colourtune is always a good start to check your mixture.....Good luck Paul J

Hi - thanks for your suggestions.
I also suspect the pilot circuit, so much so that the carbs have been stripped & sent for ultrasonic cleaning today - fingers crossed!!!

Hi, does it leave some smoke when pulling off? I would have checked the compression on cylinder 1 while waiting for the carb to return. If that is ok it probbably is your choke on carb one that is stucked in a way. The ignition should be ok since idle and above 2000 is working.

sounds like carb problem,need a good clean out.

check compression

njwmct wrote:This is really starting to drive me crazy now!
Z1000 MKII - very low mileage motor - only 4,900 miles genuine.
Bike will not pull cleanly until it's above 2000 rpm.
Cylinder 1 plug is sooty all the others are fine.
Here's what I've done to try & solve the problem.
New Plugs.
Carbs stripped & cleaned about 4 times - all the following renewed, pilot jets, Main jets, Needle valves & seats, all o-rings replaced.
Choke plungers are all free.
Service Fuel level checked & adjusted 2 times.
Inlet rubbers removed , checked & resealed at head.
Carbs balanced.
Valve clearances checked & adjusted.
Anyone experienced a similar problem?

Forgot to say:
Engine idles nicely & pulls nicely from 2000 rpm up!

Well got the carbs back today after a full ultrasonic clean & guess what - has'nt made a blind bit of difference!! - exactly the same symptons as before.

Tried to measure the coil resistor Got readings of 2.3 Ohms one side & 0 the other - according to the manual readings should be 1.5 to 1.9 Ohms -
Could this be the problem?
Anyone know where I can get a replacement resistor block (Kaw part no. 28018-1018)?

How are you measuring coil resistance?
Primary resistance between black and green or red and yellow depending which coil you are on should be around 3-3.8 ohms secondary resistance between spark plug ht leads should be around 30k but have had them run ok about 25k,this only shows you if coils are shorted or open circuit,coils that break down are usually when they are hot and get worse as revs and heat build up.
If you are still running points have you checked/replaced condensors?
Have you checked ignition statically and dynamically?
You are not using NGK always fail brand plugs by any chance?
have you fitted new suppressor caps?..Hope this helps if not repost Paul J

remove the plug cap from the ht lead on no1 cylinder + hold it against the spark plug with some insulated pliers + start the bike. gradually move the ht lead away from the plug + see how far away you get before the spark stops . repeat the process on no 4 cylinder + check if there is any difference in the spark quality + how far the spark will jump

PAULJAC47 wrote:How are you measuring coil resistance?
Primary resistance between black and green or red and yellow depending which coil you are on should be around 3-3.8 ohms secondary resistance between spark plug ht leads should be around 30k but have had them run ok about 25k,this only shows you if coils are shorted or open circuit,coils that break down are usually when they are hot and get worse as revs and heat build up.
If you are still running points have you checked/replaced condensors?
Have you checked ignition statically and dynamically?
You are not using NGK always fail brand plugs by any chance?
have you fitted new suppressor caps?..Hope this helps if not repost Paul J

Hi - Thanks for your info but I meant the measurement of the Ballast block resistance.

PAULJAC47 wrote:How are you measuring coil resistance?
Primary resistance between black and green or red and yellow depending which coil you are on should be around 3-3.8 ohms secondary resistance between spark plug ht leads should be around 30k but have had them run ok about 25k,this only shows you if coils are shorted or open circuit,coils that break down are usually when they are hot and get worse as revs and heat build up.
If you are still running points have you checked/replaced condensors?
Have you checked ignition statically and dynamically?
You are not using NGK always fail brand plugs by any chance?
have you fitted new suppressor caps?..Hope this helps if not repost Paul J

MkII should be Ok with 2.3, I used to run 2.2 dyna coils with ballast resistor., 1.5 to 1.9 ohms for the the resistor they are usually quite stable. Doubt it's ignition unless you have a bad connection. Check the little hole just the other side of the slide is clear in the venturi, they will do what you are experiencing if blocked, Are the slides notched, they should be

Rich wrote:

PAULJAC47 wrote:How are you measuring coil resistance?
Primary resistance between black and green or red and yellow depending which coil you are on should be around 3-3.8 ohms secondary resistance between spark plug ht leads should be around 30k but have had them run ok about 25k,this only shows you if coils are shorted or open circuit,coils that break down are usually when they are hot and get worse as revs and heat build up.
If you are still running points have you checked/replaced condensors?
Have you checked ignition statically and dynamically?
You are not using NGK always fail brand plugs by any chance?
have you fitted new suppressor caps?..Hope this helps if not repost Paul J

MkII should be Ok with 2.3, I used to run 2.2 dyna coils with ballast resistor., 1.5 to 1.9 ohms for the the resistor they are usually quite stable. Doubt it's ignition unless you have a bad connection. Check the little hole just the other side of the slide is clear in the venturi, they will do what you are experiencing if blocked, Are the slides notched, they should be

I was messing around with the bike this afternoon & No.1 does not respond to pilot screw adjustment at all.
Any idea where the small venturi hole runs to?