I opened the crankcase of my scooter (PGO PMX Naked) to have a look at the clutch, and there was a gasket between case and cover. It looks like some type of cardboard material, extremely thin. Since the crank case houses dry parts, and has an air intake, I can't think of a reason why it would need to be sealed with a gasket. It is really hard to find PGO parts, specially where I live, but I am a bit afraid of putting it back together without knowing the implications. What is the risk of not sealing the crank case properly?