Timing Motors Timing in brushed motors is sub-optimal as the ideal timing is continually changing as the motor load and RPM change. As the magnetic field in the armature increases, it interacts with the magnetic field in the can, and the resultant magnetic field is slightly rotated. Ideally the timing should be changed by this same amount of field rotation. However this field rotation is directly proportional to the current draw of that particular motor. Additionally the windings of the armature act as an inductor (an inductor is basically a coil of wire which "resists" changes in current in the same way a capacitor "resists" changes in voltage). Higher and higher armature speeds require the coils to be energized sooner and sooner so that they come up to full magnetic field strength early enough to fully react with the field magnets.  A side effect of the optimal timing angle would be minimized arcing at the brush commutator interface. Since increased timing should make a motor work better under both high torque and high speed situations, you'd think more timing is better, but it is very easy to give a motor too much timing. I use a timing stand so I can be accurate and repeatable in setting the timing as the can markings are often incorrect.
How much Timing For better performance you want to advance the motors timing. That means turning the endbell in the opposite direction that the armature spins. How much advance? Really its trial and error process, sneak up on it a few degrees at a time. You will notice more top end speed but less low speed punch.  I'll provide some rules of thumb to help get the timing in the ballpark so you can minimize your tweak time. First step is to set your timing to zero or neutral timing. Now use a 4 or 6 cell pack and hook up a current measurement meter such as a DVM or an Astroflight super watt meter. At zero timing record the current draw and then advance the timing until the current increases by 5 amps.
The final level of advance to get the 5 amp increase will vary with the number of turns - lower turns less advance - more winds more advance. You will find that you can easily increase the power output 30% and torque 25% from a neutral timed motor. Of course not everything is better, current draw is up so run time will be down and motor, esc and battery heat will increase, watch the heat! Lastly the timing advance will also increase the rpm, so its important not to over prop this combination. | 
