Originally posted by drift
air shifters require a ratchet or sequential shift transmission. they're primarily for drag racing in a "semi-automatic" configuration and normally they're only designed to upshift.
i've seen some air shift setups on street bikes tho.
finally! an intelligent response. they make upshift and downshift versions but usually they are equipped on automatic transmissions that have been fitted with a manual valve body reuqiring you to selct each gear individually.. imagine it as a clutchless manual tranny... but with worse shift points. lots of motorcycle guys use them as their trannies are sequential shift, meaning you perform the same action to go thru the gears as opposed to moving up for first, down for 2nd, up again and over for 3rd and so on.