[Tom Ore]

We had the same problem with our minibot deploy arm. We replaced the denso motor a couple of times during the season to keep it tight. We did take one apart to look at the coupler, but I don't have a good fix to recommend. (For a competition robot it probably isn't legal to modify the coupler.)

EDIT: Our problem was the rubber coupler inside the motor. It's in between the gear and the output shaft. If you grab the output shaft and turn it back and forth, you can feel the extra backlash. I assume the rubber is taking a compression set.