Bike carb running issues: poor idle, missfire, won't rev

[Lewis.]

I've just fitted a set of ZX-9 carbs (Keihin CVK40's) to my 1.4 SR, and have some fairly serious running issues.
it startd easily, and idles (just barely) on 1 cylinder, and is very reluctant to pick up when you open the throttle. however, if you use the choke, you can make it rev up on 4(ish) cylinders.
only cylinder 2 is running well, as its exhaust runner is hot, (instantly evaporates water) whilst the others are comparitively cool.

on advice from the interwebz i've tried blocking the air jets. it then idles on 3, sometimes 4 cylinders, but still doesn't rev up properly. the only air slide that lifts is number 2, the other dont move. i've stripped them and lubricated them all again, but it made no difference. the diaphragms are all undamaged and seated properly, and the vacuum passage clear.

so from this, i reckon 2 is fine, and 1, 3 and 4 are running lean because the needles aren't lifting. anyone have any experience of these particular carbs? or just know why the slides dont lift?

i'm getting pretty annoyed now, and even considering putting the pierberg back on :(

[Balley]

considering putting the pierberg back on :(

Don't be Gay, can't be anything to serious! try swopping the carbs round if its not to much of a job

[MattBrown]

Arent zx9r carbs vaccuum sliding?

Are they set up for the engine? As if they run better on choke, thats saying to me theyre far too lean?

When you rev it, are the sliders lifting? Thus pulling the needles out of the jet?

Also, try moving the needle to the top clip (ritchest one) on the 4 carbs, see if anything improves?

[Lewis.]

they are vacuum operated. main jets are 1.6mm, standard pilots, which should see it run ok, only number 2 slider is lifting. i agree it is definitely running lean obvious as only 1 slider is lifting. the needles aren't height adjustable either.

tbh its more a case of why the sliders wont lift, than why it wont run properly, as its obviously running crap due to the sliders


Don't be Gay, can't be anything to serious! try swopping the carbs round if its not to much of a job

bollocks to swapping them round Dan lol

[MattBrown]

Sounds odd to me.

Do they lift if you finger them (Ohh err:p)

[Lewis.]

Sounds odd to me.

Do they lift if you finger them (Ohh err:p)

lol aye, they do
I have had some expert guidance today, so fingers crossed its sorted. i'll know in the morning