Sooting Plugs

[ZedHead]

My Z1b has always run rich since i bought it so i too the plunge and fitted new carb kits. Bugger is that the problem still remains. I can get a nice blue flame on the Colortune at idle but as soon as i open the throttle it turns yellow, even with the needle at the lowest setting, circlip at top notch.

Any ideas?

[ZedHead]

Starting to think Needle Jets as these were not in the kits I bought from Z Power

[Ginger Bear]

I too would suspect the needle jets, they are supplied with some Keyster kits, but that's probably a bit late for you now.

Try www.motocarb.co.uk they may be able to supply the parts you need.

[Pigford]

Make sure the ignition is 100% - a good +12v to the coils, etc

[ZedHead]

Make sure the ignition is 100% - a good +12v to the coils, etc

I have Boyer electronic ignition fitted. is this relevant?

[z1bman]

have you checked your compression?

[ZedHead]

have you checked your compression?

Not yet. Has not really been suspect up till now. No blue smoke for example

[z1bman]

a friend of mine (steve r1) had problems like this his bike didn't smoke either + performed pretty good but when we checked compression it was down to about 80 psi

[ZedHead]

a friend of mine (steve r1) had problems like this his bike didn't smoke either + performed pretty good but when we checked compression it was down to about 80 psi

Okay, good advice. I give it a go in the hope you are wrong :-0

[750steve]

Did you try running a slightly hotter plug? (if comp is found to be ok that is)

[ZedHead]

Okay, I have ordered a comp tester just to be sure. I have also had an interesting conversation with the guy from motocarb.

Understandably he did not want to give away trade secrets, but he did say he has worked on lots of Z1b carbs for the same problem and that it is best to stick to original needle jets if possible. Keyster have acknowledged that theirs are oversize. Corrected size due out shortly.

As you would expect float heights are critical as is the choke set up. I will look at these again this weekend along with the compression.

Let you know what I find, if anything.

[njwmct]

My Z1b has always run rich since i bought it so i too the plunge and fitted new carb kits. Bugger is that the problem still remains. I can get a nice blue flame on the Colortune at idle but as soon as i open the throttle it turns yellow, even with the needle at the lowest setting, circlip at top notch.

Any ideas?

Had a similar problem with my Z1000 MK2 - turned out to be the needle jets - they were corroded & were letting fuel up past the needle from the main jet when at idle/just off idle it should have been fed by the pilot circuit - as a result it was way too rich at the bottom end.
Replaced the dodgy needle jet & away she went sweet as a nut.

[ZedHead]

Looks like low compression. I have tried oil down the bores with no real change so i am suspecting valves. I am going to get a leak down test done before i start taking the head off. Does any one know of someone that does this around in North Yorkshire, South Durham area.

Also, can someone recommend a good head man?

[pertonpc]

If you contact Dave Marsden at Z Power or look on their website at the rebuilds section there is the name of someone up your way that he uses for engine and head work I believe.

I just had a look and I think he uses Alan at Kipkawa for his valve & head work. Try here - http://www.kipkawa.com/

....don't know if anyone uses or can recommend them??
From Mark

[ZedHead]

Took the head and barrels off today. Pouring petrol down the ports reveals nothing on the exhaust side but is pissing out from the supposedly closed inlet valves!

Before i stripped it down i pumped up each chamber with a foot pump and a home made Schrader valve with a 14mm thread to go in the plug holes. This managed to produce some pressure in the crank case and the ring gaps are on the wear limit. So new rings needed too!

Can't wait to find out how it goes with some compression