Better motors are the way to go. All my Athearn rebuilds have Kato motors. Same hex drive, same four screw mount and only a little material needs to be removed to fit.
When you think about it, if the motor doesn't have enough torque to turn against the minor load of the brush spring it won't be much good for moving a train. The problem is the poor magnets, but it is easier to replace the motor.
I've read about motor re-builds that replace the magnets, never tried it. Not sure if it's something I would try, instead of moving on to better motors.
But who knows, if you've done it, and works, great!
Mike.
My You Tube
Maybe a new motor magnet would be better.
I wouldn't mess with the brush springs, as it might cause arcing, due to not enough pressure on the brushes. If you must shorten the brush springs, do it a little at a time, rather than lopping off a third of it to start.
As to locos not running well, many just need to be broken in. I have taken rough running locos and put them in a consist of three locos and run them around the layout for an hour or more, and they run more smoothly. I had to literally drag a couple locos around the layout a few times, but they smoothed out nicely after a half hour or so.
I've read the same, but I've never tried it, as I'm picky about what Athearn BB locos I convert to DCC. If they do a good job at slow speed, and start at a low voltage, or amps, or whatever, you know what I mean, in DC, you start moving the thottle up slowly and loco starts to move, then I consider that loco a good candidate for converting to DCC. For some reason, different Athearn releases ran different. For an example, I've never owned an Athearn BB GP50 that ran bad. I don't know if it's the motor, or what. I've had GP30's and SD45's that will run like crap, and a few that run great.
I have tried this with the old Bachmann, Tyco, Life Like, "pancake" motor, as it was supposed to have the same results, and it didn't seem to make a difference. I was desperate to get good slow switching speeds, with the train-set locos I had, before I could even think about buying a new BB Athearn loco, new in the box!
I recently read in an Athearn "maintenance and upgrade" that you should cut a 1/3 of the motor brush spring off. The article when on to say "What this does is decrease the pressure the spring places against the brush, creating less friction against the commutator, allowing the motor to run more efficiently. You're slow speed performance and low-end torque will definitely improve". Have any of you done this? Did it improve your slow speed performance? I also read in another MR topic that this risks "arching" to take place when you do this and is not a good idea. Please share your pros and cons if any. Thanks.
JRP