I have seen pictures of scooters that have had Mice build nests inside the air filter box, and also Inside the exhaust side of the CVT.
I bought some metal Mesh 1/4"x1/4" square, and put it over the air intake on the air filter box, and on my CVT air outlet, Not the inlet that has the foam filter, but the outlet, i have heard of guy's going to start their scoot after the winter and damage to the belt.