Anyone ever had any success fitting new brushes to a YDK motor? I had one and found that one of the brushes was sticking in its slide cartridge, freed it up, and away she ran.
As was very little depth left on the brushes I thought I would treat it to a new set, duly purchased and fitted, hey presto sparks!!!, gratitude I thought.
Why did this happen?, not a huge amount of sparks, but the original once working had only tiny sparks on brush contact edge only, whereas new had several tracking lines trying to go round the commutator.