Well I pretty much have rebuilt my c4 twice but this time it does ok for a few minutes ( if I spray a little lubricant where the motor and those hexagonal pins come together ) and then I guess the lubricant washes off and it starts to bog down again. If I take a pair of pliers and try to turn that motor pin it is really hard .. it turns but it doesn't want to .. ???? Any input is there a lubricant I need to be using ?