Where did you find a slipper clutch?needs that backpressure on the stock motor. Big exhausts on stock motors actually reduce power. I don't run it just so the bike is loud and the idiots on the road can hear me. A little power isnt worth my life. But I got a 178cc TB kit with V2 head going in it soon. Just waiting for my slipper clutch to get here and then the build will start.