I have a zxr750J and it runs very poor under 3000 rpm.
The carbs are clean and no leaks between carbs and cylinderhead.

I disassambled the carbs and the main jets are 140 dynojet - ALL 4 !
Is this not a problem , the std is 132 (1+4)/138(2+3) ?

I'm not very familiar with dynejets, can anyone tell me if this can work or I need to find a std. set of main jets ??

Maybe you´ll get further Informations from Micon Systems

http://www.micronsystems.de/" onclick="window.open(this.href);return false;

They also sell invidual jets.

I wil try that.

But doesn't anyone have a dynojet-kit in a J ?
What size jets do you run ??

In dynokits not only the mainjet is changed, also the needle and idlejet too. If you like to change back to standard, you need to replace all.

I run standard 132/138.

pilots are #38 as STD ??

needles have 6 groves where the clip can be placed and 3 rings above the clip.
size of main states #140

in my opinion this is to large for a std. J-motor - any ideas ?