Bad MiniCIMs... failing to consistently start?

[SJaladi]

As Mike already mentioned, running shooter wheels directly off of the motor shaft is not the best option due to the radial loads the ball puts on the shaft (1923 did this in 2013 and 2014 and it was definitely not the best idea). However as it sounds that you are constrained by your design, a better solution than pressing the hex adapter onto the shaft, which may cause damage to the internals of the motor, is to use the 8mm to hex adapter which is available from both andymark and vexpro.

http://www.andymark.com/product-p/am-0588.htm
http://www.vexrobotics.com/vexpro/ha.../217-3255.html

Alternatively if you have access to a lathe and the correct broach you can make your own adapters very easily. (We made ours with a drill press but it was a last ditch effort as we didn't have access to a lathe, and the COTS ones were out of stock)