One two weeks ago, the other one I got last week.

Also, if the shimming was off, wouldn't the rate of fire be lower than 30 RPS?

The shape could be a factor, but it shouldn't wear out the motor unless it's way off. In that case, you'll never be able to get them to mesh. But running a bad shimmed bevel gear could cause the motor to work a lot harder. I've had no issue running the lonex motor with Modify gears, so that isn't the issue. As for rate of fire, you'll have a slower ROF, but if could be much faster if shimmed correctly. The A1 is a very high performance motor so getting 30 RPS is easy with a lipo.

The motor just burned out. I reinstalled the stock motor and tested the current, there is also no more black residue coming off. Is 14 amps normal? CA high torque motor, m120 spring, standard gear ratio, 11.1v 25C li-po.

That's normal.

So that would suggest the shimming and wiring is fine wouldn't it?

Depends. The pinion gear to bevel gear spacing likely aren't identical when you swapped motors.

I would say it's "good enough", but no way of saying whether it's optimal unless I have it in front of me.

And yeah what coach said.

Wouldn't swapping pinion gears be a solution?

Just did that, same problem. CA motor using Lonex pinion, works fine.

I would suspect that Lonex motor brushes have far higher carbon content than the CA ones. An acceptable RC motor has Silver content in the ~30%+ range. Silver is not cheap, I suspect that LONEX is getting brushes from a different source as their older motors don't appear to have these kinds of issues.

The other possibility is that the commutator is damaged or not manufactured smooth or round. less likely the armature could be just slight off from being straight, or the bearing / bushing that it sits on isnt seated correctly.

Their was a post by KOS MOS on where to find replacement motor brushes. If it's a more sever manufacturing defect you are SOL unless you want to DIY a fix

Some day ill get a comm lathe and y'all can send me your lonex motors for testing

I tried CA and Marui brushes on the motor and those burned out in a couple hundred rounds. Sounds like I got two crap motors in a row.

3rd time's a charm?

Honestly we've serviced two warranty claims in April/May on this issue. The replacement motors have been reported to be fine.

Probably just have shitty comms on them
Even systema PTW motors are reported to come with mostly egg shaped comms