Food for thought: What does the triangle of combustion has to do with running-in (break-in) a new motor?
If you place the new motor in a jar 3/4 filled with methylated spirits, cover the jar tightly but leaving the motor-wires outside the jar, you can then run the motor at full for approximately (motor has to remain submerged) 2.5 to 3 minutes. This affords the brushes to conform and for the armature shaft (fore&aft) to wear-in without overheating, whilst the motor remains internally free from carbon deposits and airborne charged-particles. Remove the motor from the jar carefully (warm spirits) dry off by manually turning the shaft in front of a slow fan or hair dryer, allow to cool if necessary. Lubricate with your preferred lubricant (KY? lol sorry) run for half a minute without load at full. Ready for installation.
TRIANGLE OF COMBUSTION.
Re: TRIANGLE OF COMBUSTION.
Glad you posted this tip Richard. I have actually done this many times in the past, although not so much recently. Here's a pic on my workbench from some years ago:
