Carb Air Screw and Pilot Screw

I purchased my KZ900 in 1995, so I don't know the complete mechanical history. The carbs may not be the original, I don't know for sure. They are 26s, I am sure of that.
The problem is these carbs have both the standard air screws I am familiar with and the pilot screws on the under side of the carbs between the bowl and the intake boot.

My Kawaski Clymer manual gives the carb specs on the models 1973 through 1979. According to the manual, no carbs have both air screws and pilot screws and the starting adjustments if you have both.

Any thoughts are appreciated.

Pics would definatly help

WMKZ900 wrote:

I purchased my KZ900 in 1995, so I don't know the complete mechanical history. The carbs may not be the original, I don't know for sure. They are 26s, I am sure of that.
The problem is these carbs have both the standard air screws I am familiar with and the pilot screws on the under side of the carbs between the bowl and the intake boot.

My Kawaski Clymer manual gives the carb specs on the models 1973 through 1979. According to the manual, no carbs have both air screws and pilot screws and the starting adjustments if you have both.

Any thoughts are appreciated.

Stock KZ900 carbs have only side-located pilot air adjustment screws.

Have heard of but am unfamiliar with carbs having both style pilot adjustment screws. But have also heard that tuning their pilot circuits is by closing the mixture screws and using the air screws in the normal manner. Seems logical to me.

Good Fortune!

[Click on image to enlarge view.]

Its the same adjustment as single screws, just more difficult! :blink:

Set them all to 1.5 turns out from lightly seated.

Ride the bike for about 15mins in order to have it come up to proper operating temp.

Point a BIG fan at the engine/headers while you do this, and be careful not to burn yourself.
Run the bike.
The air screws (closest to airbox/pods) should be adjusted first.
It is easiest to use a good vacuum guage or external tachometer (for visual confirmation), but it can be done by ear.
Turn the screw 1/4 turn at a time in, until you see/hear the engine rpm drop. Then turn the screw out 1/4 turn per say 3 seconds, (Count the number of turns!) till the rpm drops again. Then turn the screw back in to the middle/half the number of turns you counted, between the two rpm drop points.

Do this for all the air screws, then do the same for all the mixture screws (closest to engine side of carb), and your done.

Remember to return the bike to proper idle rpm via main idle control after you are satisfied with screw setting, per carb.

Dont let the bike overheat! It will take quite a while, but you should stop and let the bike cool 1 hour if your adjusting for more than 15 minutes. USE BIG FAN, and you can continue to adjust for as long as you like.

Good luck!