Clutch Operation: I got this information from WWW.NitroRC.com, hope it helps you. If you go to their website they have several helpful diagrams as well.
R/C car engines rotate CCW (counter clock-wise) As the engine increases revolutions the leading edge of the clutch catches on the clutch bell and aggressively transmits the power from the engine to the clutch bell. This power is then distributed through out the car's drive train and eventually to the tires...
The stock clutch setup loads the engine with the strain of trying to accelerate 5+ pounds of car and at the same time the engine attempts to quickly accelerate to reach it's higher power band. 2-Stroke engines increase power output as the RPM’s increase. So if you want to use more of your engines available power when you need it the most (quick acceleration on the corners). You need to let the engine engage at a latter time when the RPM's are higher and when the engine has more available power to accelerate the vehicle.
You pull the clutch shoes off the flywheel and flip them around and re-install. This mod basically changes the power transfer when accelerating because now the trailing edges of the shoes engage the clutch bell. This allows the clutch to slip a bit for the engine RPM’s to build and jump starts the torque level when accelerating from the corners. It is very important when you flip the shoes that you don't pinch the clutch spring with the flywheel pins. You can push a small allen wrench through the pin holes to push the spring out of the way as you press the shoes against the flywheel. Reinstall the clutch bell parts in the order removed.
I accidentially put my clutch shoes in trailing edge and the CB and spur are engaged at idle. It was not like that before I installed my new CB. I am going to switch it back to leading edge. The stock clutch spring must be a little on the weak side.