Re: i been riding with air filter off, can it do harm?
Velocity stacks are used by racers who expect the most out of their motors for short periods of time. Race 2 strokes need completely rebuilt about every 10 hrs of run time and get top end attention more often than that. Most people I've known to race 2 strokes use filters even a drag racer I knew. That Unifilter Spooky Tooth sells is a race quality filter.