Motor timing on a brushless RC motor is how far the sensor endbell is rotated relative to the rotor, advancing when each winding fires. More timing adds RPM and heat; less timing runs cooler.
You set mechanical timing by loosening the rear endplate screws and rotating the endplate against its reference marks. Hobbywing’s XeRun V10 G4R manual gives a 20–60 degree adjustable range with a 43 degree default, and states plainly that increasing timing “increases the motor temperature and reduces the efficiency.” Hobbywing’s own advice after a change is to run a full pack and check with an infrared thermometer, then reduce timing or gear down if it’s too hot. Class rules govern how much of this you get to use: spec and stock classes commonly require a zero-timing “blinky” ESC — ROAR specifies it for classes like FWD and LMH — and clubs differ on how much timing they allow on the can. Read the rulebook first.
Timing is the fastest way to add power, the fastest way to cook a motor, and in a spec class the fastest way to fail tech.