Sure, its very simple really, the one way(drawn cup roller clutch) functions(grabs) in one direction but not the other direction of rotation. So when your rototech spins in its intended direction it grabs the shaft that engages the crank and spins the crank. Now when your engine starts that same shaft is not engaging the one way allowing it to spin. So when your oneway has failed it no longer grabs the crank and seems as tho it spins freely, sometime it will even grab and seem to work intermittenly. Cleaning the oneway regularly will help prevent the failure.

I hope this helps!!