3500-3800 are my usual picks. 4200kv would be my second choice.
Just an FYI KV does not mean kilo-volt when talking about brushless motors. KV means for every volt put into the motor the motor will theoretically spin 1000RPM. Kilovolt means 1000 volts so a 6000 kilovolt motor would be a...
that would not cause that issue. Its most likely a programing issue either on the ESC or the transmitter. That would be my guess as I'm not familiar with that kit.