Hobbit, stock PA50II carb/intake - In trying to tune, I down jetted from 90 to 86, which helped but it still 4strokes a bit till it gets hot after few miles. I thought i'd look at the filter box but it looked ok. I dont have the snorkel in cause its a PA50I, but I took it for a ride without the filter box and it ran awesome, great power and hit 45 immediately? I took some pantyhose and threw it over the carb intake to avoid sucking anything into it as a test and it runs great - what do you think is going on?