Can I overvolt a Neu ?
 

If it is rated for max 12v can I run 14v on it occasion?

Which motor, what setup, what gearing?

Neu 1110/1y In my mini revo with 4s 67,000 motor rpm by the calculator...I plan to almost always run 3s but might try 4s on occasion

Just try using 3s first. After that I bet you won't even consider running 4s unless you are crazy or are geared too low in the first place.

Yeah, you won't want to even run 4s anyways, it will literally fly on the 3s. No, you shouldn't really run the motor at those speeds for very long at all... besides, what controller were you going to use? The controller might not even like 67,000rpm, could overheat.

I tried to run a Quark 125B with a BEC and a Neu 1515/1d 4400 kv on 4s and melted/smoked the Quark.I wont try it again.