i had the same problem with my sidewinder 5700 (same motor) i spoke to castle and they said to send my motor in for replacement because it had " demagnetized" .i was running 200 degree temps on a 13/87 gearing and ib4200 batteries. the new motor runs 150s with 19/87 gears and low timing. by the way, my rustler has a faster top speed with low timing than high timing