Just about every video I see of someones 2 stroke scoot (ones that are running great) they have smoke pouring out of their exhaust, I know some people would prefer not to but I like the idea of it smoking up a lot. My scoot is pretty good, only smokes a tiny bit on start up/low revs. What causes this, type of oil used? (fully synthetic etc) carburetor settings? higher oil to fuel ratio?