this is probably a repetitive question.... how can you tell when it is time to replace your brushes?(i think those are the little silver wires that look some what like a spring[&:]) (if someone could give me a web site with the parts of a motor i would appriciate it.)

alex

You replace them when they are discoloured, or when you get a comm cut. If the motor only goes when you push it, you are badly in need of new brushes.

[&:]whats a comm cut?

The "Com" or commutator (in layman’s terms) is the internal part that spins in the motor
The location where the brushes contact the Com, every once in a while, needs to be "Trued" with a "Com Lathe"
After this process the motor, with new brushed, is very much like new

Most serious electric racers cut their coms very often
The look like this
http://www2.towerhobbies.com/cgi-bin...&I=LXNB54&P=ML

you replace the brushes if they become discolored or if they become half the length of a new brush. When the brush becomes discolored it actually is much harder and looses its lubrication that is built into the brush and it is much harder on the comm wearing grovves in faster. Discoloration can be caused by motor overheating... make sure you do the 5 second finger rule. Touch the can for 5 seconds if it hurts to touch it or you can't hold your finger there it's too warm go down on pinion size.