I just bought a Mk1 Fireblade which was only running on choke, every time you blipped the throttle it just bogged down and died, I could get the thing revving but the noises coming out of the engine were horrendous.
Stripped the carbs down last weekend and cleaned all the float bowls, jets, idle jets, choke system etc... and cleaned out the fuel lines.....
Cant believe the difference, it starts on the touch of the button and revs really well with no hesitation.....
You might need to give em a damn good strip down, its amazing the difference a clean carb can make..... Might sort out all your woes mate.

 

Ok, so nothing has changed with the timing, so leave that one.
I too am going through a real headache on my zzr and cannot get to the bottom of it.
As for fuel never buy supermarket fuel. If you can get to a well known company BP, CALTEX, TEXACO, ESSO, they have high octaine fuel, 96/97/98 somewhere there.
Check the pilot jets/ screws. The jets have a good many orifices and can get ‘filmed’ with dry fuel coating.
Check for water in fuel bowls,and check the float needle/ seat and height at which the float cuts of the fuel.
I heard of one guy who lowered the front of his bike, which in turn altered the level at which his float stopped the fuel.

 

Have you done the stick coils upgrade???
It made a noticeable world of a difference on my '88 Hurricane 1000F on idle, acceleration and throttle response.

 

Yep I did. Works well, very pleased, think I used R1 coil jobbies.