How do I remove the "speed reducer band" on my KFX 90 atv?
The dealer told me it would increase the speed of the 90 by about 5 mph

 

Welcome to KF.

Not quite sure on your question, but a band "speed reducer band" may be a washer limiting the full throttle throw at the lever? Good question. Let us know and good luck

 

This is an old thread but I think useful,
I have one and my son wanted to go faster,
so
safety in mind the quick answer is
remove the clutch cover and kick start,
my best way sofar is wrap a towel around the drive clutch so it pinches and prevents its rotation, DO NOT use plyers or screwdrivers, the belt cannot be tightened enough to stop the clutch rotation. (tried that too)
Remove nut, then clutch assembly, seperate disks (caution not to lose rollers/ weights) remove limiter ring,
reassemble tighten to proper torque, then reassemble rest of machine.
The above mod will allow the clutch to engage fully, tested against my wifes Forman 500 it maxes out at 30MPH on flat sand. the throttle is still limitable.
be safe