Quick UK alloy cooling fan

The base of the cooling fan, when installed, rubs on the drive belt.
As a result: the main rotor engaging constantly

Solutions:

• Buy Kyosho clutch upgrade which has an upper and lower aligner to keep the drive belt positioned.
  “Less vibration and better driving efficiency are newly realized. Flange is molded onto the pulley due to prevent slanting of the belt.” from Kyosho upgrade page