by Nec » Wed Jul 21, 2010 8:18 am
The only thing that needs to be broken-in are the brushes and they usually come prebroken-in from the factory. It's only when you replace the brushes do you need to break them in.
As for maintenance cleaning the commutator of carbon deposits left behind from the brushes can increase performance quite a bit.
To clean the Commutator, use 600 grit or finer sand paper to removes the chips and carbon deposits off.

There's a difference between a person who has a screwdriver and a person who knows what they are doing.