I need to swap the piston and rings in my 87 KX500 and was wondering if I can do the swap in the bike. I have roughly 2.5-3" of clearance between the head and the frame. If I pull the head off, will I have enough room to get the cylinder off if I get the piston to it's lowest point? Is the exhaust valve bolted in the head, or will it just fall out when I lift the head off? Sorry about all the questions guys, I'm just new to tearing bikes apart.