If you need a better mesh with your main gear than you currently have then consider upgrading to one of the Align pinions. With deeper teeth they mesh better meaning less binding problems and a quieter heli. In addition they are easily removed/installed due to the grub screw. This means no fiddling with pinion pullers/fitters! They come in a pack of 3 with 9,10 & 11 tooth pinions and grub screws.