Zx6r running issues

[sam-parsons-13]

Hi all. Having a bit of trouble with my zx6r. It's a j1 carb'd model.

When you get to about 9k on WOT it starts hesitating then surging and won't rev cleanly to the redline.

The o my modification it has is a 4to1 exhaust with a large venom end can.

It has recently had a full service including air oil and fuel filter spark plugs and oil. I have also fitted a new jet kit. From Ivan's it included new needles and main jets and settings for the pilot screws. The only thing I couldn't do was drill out the main air jets as instructed as I didn't have anything that would hold the tiny drill bit.

Any help or guidance would be much appreciated thanks

[DynaMight]

Make sure the pipes for the airducts have been reconnected again, I know from experience that the thing barely runs if these pipes are not connected.

The pipes are usually around the headlights-ish area, its not a massive pipe either, about the size of a fuel line.

[graham22]

I'd be inclined to get the jet kit correctly installed. I'm struggling to understand why jets need to be drilled out rather than swapped over to bigger ones(?).

Either that or take it back to standard but I guess the jet kit was bought because the original needles had worn?

[Ducaki]

As already said.
Compleat the jetting kit as the instructions, before you start chasing your own tail.