Hello, I was looking at my engine there earlier, and on the piston, it says "IN" on one side of it, with a little depression there for a valve to move down into. Does this mean that this side of the piston should be the side the intake valve is on? Because if so, the person who had this bike before me must have put the piston in wrong. On the side opposite the "IN," there is a little ding in the metal as if a valve had tapped it. Let me know what this "IN" means!!!

PS: It's a 1983 ATC200

 

You are correct. The "IN" side of the piston goes towards the intake side. Sometimes logic does not prevail!