My bike has been hesitating from 4k - 5k while accelerating. I messed with the vacume hoses and fixed it by taking the Air Switch Valve out of the circuit. What problems will I cause if I just cap the vac tube on the switch valve?
Bob is correct. It is a good, simple system that allows the exhaust system to pull fresh air into the header tubes between exhaust pulses (low pressure periods). That burns up unburned fuel. I am the furthest man from a tree-hugger you're likely find, but it IS good for the air we breathe. It uses no power, no fuel and it's only downside is some exhaust popping on overrun. It might also screw up mixture readings on a dynomometer. I say fix it as soon as practical. Run as is 'til then.
What Steve said.... I have done this on 3 Kawasaki four-cylinder bikes including the Concours and it works great.