does the 550 switch have a park position ? if so you won't need them 2 wires. basically you have a live wire up to the ign switch and with the switch in the ON position you should have live coming out of the switch. thats how my 750 is wired
when i built my Katzuma i put the engine in the frame, then i found a standard airbox, but when i come to fit it, their was no way it was going on !!!!!! luckily i only had the engine in the frame at the time
sounds like it was drawing to much air, people have had some success with wrapping half the air filter to restrict the flow. but defeats the object of fitting separate filters. by the way you can't fit an inazuma airbox with the engine in the frame
the seat isn't shown in the pic but it is in the list below, I didn't know they where available from suzuki as they are pressed in !!!!!
the bandit 1200's seat is held in with a small plate and screw.
CARBURETOR for Suzuki GSX 750 2000 # SUZUKI MOTORCYCLES - Genuine Spare Parts Catalog (bike-parts-suz.com)
this is why i said about B6 carbs,
i put a set of b6 carbs on a b12 engine without changing anything, they worked spot on. even though the jetting is slightly different on the 1200 inazuma.
I have a bandit 600 rear wheel in a 1983 GSX1100 swinger (on my GS750), when the wheel is adjusted forward the tyre is very close to the inside of the arm, so I think you might have clearance problems ??????