I demagged my HV4.5 5mm shafted rotor. I put the orginal rotor back in and it worked fine. The motor had a burned smell too. You can always send your motor to Novak with the demagged rotor installed and they will replace it with less than the cost of a new motor.
Check out my custom converted 8ight:
Sub 7lb, lowest CG of any 1/8 buggy