I own a 2004 Bandit (Canadian Edition). I have done some extensive experimentation with my bike and the best setting with a Yoshimura RS3 with a Zyclone baffle are:
With the snorkel on: main Jet: 102.5
Needle: Stock with a shim of: .064mm
Pilot screw: 3 ½ turns
Without the snorkel: Main jet: 107.5
Needle: Stock with a shim of: .05 mm
Pilot screw: 3 ½ turns
The difference between the snorkel on or removed it is the top end performance. With the snorkel on your bike will pull hard up to 8,000 rpm. Without the snorkel it will pull harder up to 9,500 rpm.
I have tried Ivan’s jet kit with both configurations:
Holes in the air box has recommended and snorkel removed
Main jet 112.5
Ivan’s needles, third clips
Pilot screw 3 ½ and 4 turns
Yoshimura RS3 Zyclone
It was running to rich in hot weather and to lean in cold eather
I have noticed if do some extensive modification in your air box, your bike will be more sensitive the temperature changes.
Only snorkel removed
Main jet 100
Ivan’s needles, third clips
Pilot screw 3 ½ and 4 turns
Yoshimura RS3 Zyclone
It was slower than a stock bike, it was running lean