Well it happened the pinion transfered from the stock motor to my brush-less failed along with the stock main gear. No sense spending another 16.00 for a new motor just to get the pinion. So it was time to do something about the lousy gear selection that we were limited to.

Items needed:
Dremel
MicroHeli TRex 150T CNC Main w/auto. rotate (Just happened that I had one) MH-TX4102
one shaft lock collar (Need to order one from parts list)
one pinion (I have just happened to have a 14T from My 450XS)

UPDATE 4/9/2007 ONE CAN ALSO USE THE ARK X-400 GEAR TOO MH-XH4102

1. Make a mark with a marker between swashplate and the top of the upper bearing housing (on top of the plastic) to keep shaft alignment, this will keep pitch settings.
2. Needed to grind the back-half of the gear housing to match the front half
3. There is a screw hump in the front of the motor, needs to be ground smooth for motor adjustments
4. Leave the bushing that goes on the lower bearing in place and test fit gear-look to see if more needs to be ground off
5. Install upper bushing-upper shaft lock and lower gear shaft lock. Verify shaft position from mark made earlier
6. Install Motor and pinion, Make adjustments for pinion height and gear mesh

I did a bench test and all seems to work well.