Rev Box

[crayztwentyseven]

Anybody ever use one of those aftermarket rev boxes thats supposed to add to the limiter or run different timing and fuel curves? A buddy of mine put one on his bike and said that it worked good. The problem with his report is that he put on a Yosh pipe at the same time. ? So how does he know if the black box is doing anything at all? ? I've seen them for sale for a while I was just wondering if anyone had tried one and noticed a change. Without doing some other mod at the same time. ?