the reed spacer is either there to increase air speed going into the reeds i.e. better flow at top end. or to decrease air speed going into the jug i.e adding throttle response or torque
WTH is up with people digging up old threads and bumping them back up lately???
Reed spacer= junk. Only useful purpose is to clear a bigger carb, but there are other ways to clear a bigger carb ( tilt it slightly, adjust the clutch ect.)
I have a 1/2" spacer and it was just to clear the 30mm carb from the clutch lever, It was too much of a tilt without. I didn't use it for any performance gains or loss. If i gained whoo hoo, if i lost, boo hoo. It still hauls ass,