I am currently using the Hobbywing 21.5T V10 G3 Xerun motor.
The event rules state 2400Kv, max 1.5amps
Now on the motor checker, my motor is producing 2434kv @ 3.6amps
The G3 comes standard with a 12.5mm rotor

Question, with out purchasing a load of different rotors, what do i need to bring the amp draw down to 1.5 amps ?

Cheers

If that motor has adjustable timing, try dialing it back a couple of degrees. Shouldn't take much.

Yes It has timing adjustment....but to get 1.5amps the timing is set to the bottom of the scale and its only performing at 2050KV.
Im thinking there must be a way to get a higher KV with the same amp draw. I seen a video with a muchmore guy, but doesn't really make sense

You can try adjusting the shims, or gap between the rotor and the sensor board, typically you want all 3 phases of the timing check to be within 1° of each other and this gives you optimal efficiency which will also increase your RPM and reduces amp draw, more info on an example here:
REVIEW: NOVAK NX4-3900KV 4-Pole 540 Motor