Motorcycle Repair: carb jettin / hotter plugs, suzuki gsxr 750, air fuel mixture

Question
 I purchased a 1997 suzuki gsxr 750 about a month ago. The person i purchased it from said it has a stage 2 jet kit installed. The bike run's good I had no problem at all with it. Now a friend of mines has the same exact bike except it's a 1996 and when we go riding on the interstate or track he seem's to pull on me so we took out his jets and looked at where the c-clamp was set and his is one notch lower to the tip makeing it richer. So I did the same thing and he no longer pull's but just like him I now get a hesatition from idle to about 1/4 throttle (actually looking at the rpm from a dead stop at a light it bogs till around 3000 rpm then she pull's hard and strong )It almost feel's like it's not burning all the gas my question to you is if I purchase a hot irridum spark plug will this help or is there some kind of adjustments I need to make to the pilot system ? And if so how do I accomplish this task ?  Thank you for your time I really appreciate your help.

Answer
Hi Michael,

Nix the hotter plugs; bogging/hesitations are a symptom of a rich air-fuel mixture. You'll have to change the metering circuit for the carburetion range of idle-1/4 throttle: pilot jets and/or air-fuel screws. Start with the screws, notice changes, then try changing pilots. Make one change at a time to know the effects the change has made.

If I had your email addy as requested, I would return a variety of tuning files.

Respectfully,
Mark Shively