Proptop, I've never heard of lapping the Head to the Sleeve, how is that done?

Definately looks like the head was unevenly torqued down to the case, or improper torque was used. I'm not familiar with ENYA motors at all, but it looks like the head was not seated properly.

I had a nelson .40 Q500 motor a few years ago, that never ran properly from the day I got it. I tried a lot of things, but it was always about 500 rpm down from my average "good" motors. For the hell of it, I tried a different head from an older motor and it suddenly was right there with my other "good motors". I suspect it was leaking / sucking air due to a bad seal for some reason. Was a completely different motor with the different head. Can you get just a new head, or button for the motor?