On Saturday, March 5, 2011 11:28:03 AM UTC-6, Tomas wrote:
I... replaced just about every seal this thing has... I press the trigger and air comes out of the trigger but the gun does not fire (cycle).

I just spent 3 hours overhauling my Hitachi NV65AH and it was doing the same thing. After dismantling it and reassembling it I realized that the gasket was blocking the "small air tunnel" as you put it. She works like a charm.. Amazing that you can't find much info about these problems on the web today.

So, make sure the exhaust head cover gasket is not blocking the little small hole that looks like a screw can go in it (flip the gasket over). Also don't snap the exhaust valve all the way in or push the cylinder all the way down.