Hello to all!

I just bought an MC18 R5, I new in this forum and I just want to get facts and opinions. The bike looks godd and it starts after one kick, it has a lot of power and it runs fine but when I open the cylinder head and decarbonize the head and the top of the piston, I notice that there is a gap in betweent the piston and the cylinder. more like a clearance or play. when I tried to shake the piston using my fingers, it moved, not to big but a slight movement, more like a play? is this normal or my bike is messed up. I know that 4 stroke has a very small clearance, the piston is so tight inside the cylinder but I dont know about two strokes.

thanks to all.