I put my thunder alley pipe on. while I had it semi-apart, I did the BK mod, raised the needle 1 notch, put a 168 main in it. The result? Blipping the throttle results in a blast of RPM I have never witnessed from a four stroke engine of any type or kind. I so excited Im almost scared. I actually set the pump timing with the engine running, blipping the throttle and give it a twist, blip it again etc. This seemed to yield best results for an unloaded reaction from the motor. One thing I did find that I didnt expect. Both of my throttle cables were frayed terribly. Is this common? The return cable was down to a single strand! Scary when thought of broken.