Chris, Lorn,

Chris, you are right.  The bearing mount is very sensitive to any distortion, including that induced by tightening the sleeved bolt at the rear too much.  One way to relieve this is to add a thin washer on the sleeve side of the block.  Since the pivot blocks were drilled by the builder and not with a CNC, it is possible to put them back on the wrong side, rotated or flipped (they should have been marked).  This can cause a minor misalignment, ergo excessive friction.  Luckily, I have a minor oil leak from my engine that throughly lubricates the pivot during each flight.

Scott Krueger
N92EX