Ok, so how does one tune a motor? I know it's a very broad question, but I'm curious.

Thanks in advance!

Tuning an Electric motor? A nitro motor/engine?

In order to really tune an electric motor you need a dyno. You can do a pretty good job with just a motor analyzer. Just adjust the timing up until you get a big jump in current. Most people use 6 amps as the place where the amps starting really jumping up quickly. The thinking is anything above this value you are just wasting energy by making the motor run hot. On all of my motors, this sweet spot is between 45 and 50 degrees. You really wouldn't need a motor analyzer if the motors had accurate timing marks, but they do not.

On a 2 stroke nitro engine, this is what I used to do when I flew control line. At full throttle, turn the needle valve in until the motor is running the fastest, then open the needle valve about 1/4 turn and leave it there.

Nitro/electric

If electric I would say finding the wright gearing for what turn\kv your motor is..
And that would be by finding the the correct pinion and spur combination that works for your motor and how you plan to use it..

Okay you have me curious now.
How exactly do you measure the current draw from the motor?
Common sense tells me that you place a probe on the leads from the ESC
to the motor itself, Am I correct?

A motor analyser will measure the current. If you don't have one, the easiest way is to put your multimeter in between the ESC and battery. It'll be measuring the current of the ESC plus motor, but the ESC power draw is minimal compared to the motor. Just be careful you don't push the current over the multimeter rating.

Great thread. I have a volt meter, but wonder if it would be better to get a motor analyzer or the trinity motor analyzer whatchama call it. It is pricy. What do you guys recommend for a competitive racer. I have not used my volt meter yet......

A motor analyser is a useful tool, however it's not essential. If you're concerned about the price then I'd pass on it. You can find no-load current with a multimeter easily enough. If you need the timing/kV comparison readings to choose between different motors, the expense of the motors is likely to dwarf the cost of the analyser. If you just want to check your current motor, you may be able to borrow an analyser from someone at the track.

And Glenn is assuming you are running blinky and the 6 amps is more than likely for a 17.5T brushless motor.

Correct. Thanks for the clarification.

If I were to run a 21.5 motor what amp draw would I look at for the sweet spot?