On my P2V, after a rough landing (tip-over), one motor does not spin as easily as the others. It is not major -- I didn't notice it until AFTER I took it up again, so I can say for sure that it DOES fly without complaint. But when I flick the props, the normal ones will make a couple of spins while the goofy one only makes half a spin. Are there simple diagnostics I can do to learn more, or is that enough evidence to say quit flying till the motor or at least bearing is replaced? I don't mind learning how to replace parts etc. I'm new to quads but getting hooked. I'm sure this topic has been addressed but I could not locate the right information despite some searching. If I'm going to swap out motors or bearings, is there a logical upgrade, or is that hype? Sure wish I had a big local dealer.