things to avoid when modifying tail boom or gears
 

Here's a hard learned tip: when working on an electric heli---take the motor out! If ANY tiny metal filings from the screws you loosen and tighten (and I mean tiny filings) get into the motor, then chances are you'll cook something when you reattach the battery and test the heli. This especially happens when modifying, or repairing the tail boom section.[:@]

RE: things to avoid when modifying tail boom or gears
 

Thanks thats nice to know;)