i trained on the nexstar and had the same problem. the problem i had was the nose wheel does not fit snug into the motor housing and therefor has alot of slop. also the pre filed top of the nose gear i think was filed at the wrong angle wich makes it very hard to adjust the nose wheel straight. you might look at that and maybee re file a flat spot at the top of the gear to get the wheel straight with the plane. as far as any slop maybee theres a way you can thicken up the top of the gear to get a snugger fit into the motor mount.