I've had two very small niggles with the running of my zx9r, first the flat spot between 4500-5000 revs, also when trying to set off quickly in first gear, it seems to bog down under full throtle.
Now my carbs have been rejetted, to what, i dont know, also , i am running a sausage filter.
From reading various threads, it seems i need to block off the main air jet, so i gave it a trial run.

open carb
The one i blocked was the larger of the two brass holes, just left of center, people mensioned filling with match stick , and this seemed the only hole big enough to take a match.
Went for a spin everything seemed ok until higher up the rev range it sounded a bit gruff and didnt rev as freely, so i pulled the matches out, went for a spin, and it still sounds gruff and doesnt rev freely as it should, what have i done.
By the way, i do know the carbs need a little clean, and i still have the old fuel jets.

I'll ask my bro what setup he runs- he's got a Striker running a XZ9 on carbs....

Nah mate. From this thread and from looking at the Haynes manual it is described as the one in between the lower two screw holes (that hold the plastic cap on) and its the one in lin with the needle i.e. the smaller of the two.

I think your supposed to fill the center hole , but how do you get a match stick in that.

That picture is filter side.

Description
This one is plastic cover side.

I agree. Perhaps its just a shaving of the matchstick? It does seem to be that one though from the Haynes book...but then again them things have caught me out before!!
Ah edited to say, I'm lost now, hang on.

[Edited on 14/7/07 by mistergrumpy]

Right. 'Air leak jet' as its called, is the small black dot that is just outside the rim on the lower edge of the picture. In the exploded pictures in the book it shows it as removable and that thread says it can be removed I think.
Have a look at this, choose carburettor parts and have a look at part number 16035

[Edited on 14/7/07 by mistergrumpy]

[Edited on 14/7/07 by mistergrumpy]

I will get myself some carb cleaner in the morning and strip them down, then i will fill that small hole cover side, see if that makes a difference, what i cant understand ,is why ,when i removed the match sticks, it still played up.