thanks for the advice guys,
i must admit i am a bit anal about things like this and i would rather see the bearing against the sleeve as this will take the strain away from the lock collar which moved on the maiden flight.
i have found some 10mm shims from a bag of shims i bought ages ago to shim up the diffs in my r/c monster truck.
i have one that is .30mm and one at .20mm so i will try them, i also have the option of turning up a shim in the lathe, but tbh parting off a .50mm shim in the lathe is not really the done thing and would give mixed results.
a shim is normally stamped out of sheet.
the heli is smooth but while in flight i get changes in the gearing noise.
it sounds like a fluttering noise, the sound changes as the load is taken off the motor then re-applied.
maybe the motor is floating up and down on its shaft or im just not used to the sound, the motor is quite loose against its bearings, i can pull it up and down a mill or 2.
for helical gears you really need 0 free play, or as near as you can get to 0 in both shafts.
i think i will shim the mainshaft first and fly, then shim up the motor and report back.
thanks,
chris