What did I break ?

[rschoi_75]

ilpufxit, is most likely correct about your motor.

One major concern I see is your motor choice. The feigao 7L (3511kv) on 4s trying to push a revo is not a recommended choice. Most of us that use feigao's prefer the larger XL size cans, since they are more powerful, and can be geared within a wider range.

Most people also choose lower kv motors (2000-2700kv) for 4s duties, since these ranges allow you to stay within Feigao's max rpm limits. The 7L (3511kv) on 4s lipos pushes your motor past 50,000 rpms. The feigao bearings are only rated for 45,000 rpms max. You can buy some 65K rated bearings, which will help, but the motor will still run very hot.