Loose rotor to shaft grub/set screw problem.
Have anyone’s motors had the set/grub screws come loose that hold the rotor on the motor shaft? When I would accelerate under a heavy load, like quickly taking off from a slow speed, my Tacon Bigfoot 160 motor would momentarily over rev and sound like something was slipping. Initially, I thought my motor pulley was loose and slipping on the shaft, but ruled that after closer inspection. For the record, I have ground a huge flat spot on the motor shaft, and use plenty of thread locker on everything. After a closer look, I noticed that there were two set screws at the end of the rotor, holding it onto the shaft. One was loose and one had backed out so far, that it was almost ready to fall out. There was no trace of any threadlocker on the screws, which I assume to be an assembly defect. So, after applying a bit of thread lock and cranking down the set screws, it seems to have fixed the slipping problem.
Now, it seems to be happening a little bit on my SK3 motor. At least this one had threadlock on the set screws, but I added more and cranked them down.
I had a hard time finding any information or posts about this problem, so hopefully this will help someone who may be experiencing some unidentified slippage. And from now on, I’m checking these little buggers first thing when I get a new motor. Who knew Bigfoot had a screw loose?