No. 4 carb issue

[cameron]

Hi, having a little trouble with one of my zxr carbs.

The No.4 carb seems to be running rich by a quick look at the plugs.

Started it without the airbox and balanced them, on the same carb, the slide moves before all the others and bounces up and down on idle when the others are dead still.

Told it could be an O ring gone somewhere, balancing them doesn't seem to have any effect so I'm guessing it's an issue with the carb itself.

It runs pretty badly at low rpm and runs a bit boggy until around 4k when it's pretty un-noticable.

Any help is much appreciated.

Cheers

[zimm]

probably the o-ring between float valve holder and carb body

they degrade and let fuel past so the float bowl overfills with fuel.. hence boggy and rich low down, and better high up where the engines thirst keeps the level somewhere near normal.

replace all 4, or the others will follow suit pretty quickly

[cameron]

Just found out what it was, someone had obviously taken the carbs apart before and lost a tiny little part out of diaphragm.
This was the bit that was missing, going to order one now