i agree.. the also 4s batteries, and the smaller motors.. will burn up.. i suggest geting a 1700kv motor.. or a 1900kv.
i think its somehow rated like this..
a 4.5 motor is rated at 4000kv. runs on 2s motor.. thats 4000x2s means 8000kv.
a 1900kv tekin motor on 4s, 1900x4s equals 7600kv.
if you put that 4.5 motor on a 3 or 4s motor, your well over 10,000kv.. which is way too high for that motor.