Tips Wiki Check for Loose Pinion

From Heli-Wiki

If when you throttle up your heli seems to lack power, and you have to give it more throttle than usual to hover, you might check and see if your pinion is slipping. Just take a fine point marker and mark a line from the pinion to the main shaft. Fly your heli as normal, and then after the flight check and see if they are still lined up. If they are, then likely you do not have a problem, or you just experienced one of the most unlikely things to happen =P.

If they do not line up however, then likely your pinion is slipping. There are several things you could do to make it stop slipping. You could take off the pinion and put some thin CA on the shaft and let it completely dry, then if you want you could add some more CA and then push the pinion back on and wait for it to dry, or you could just push it back on. You could also roughen up the shaft with a file and try to give it some sides instead of just being round while being careful not to take too much off. You could also try some epoxy or just whatever else your imagination comes up with =)

Alternately you could also get a new pinion for the motor. They are usually about $2

If you have this problem, in the disussion tab mention how you fixed it, how loose it was to start with, and how much flight time you got out of it before failure of the fix, just so we can get an idea of what way works the best to fix it =)