[advant63]

geezer i am in southern ontario= flat as nebraska. 230 meters elevation. i'm on the stock jet, just shimmed and i don't know where the idle screw is other than where it ran best. probably close to yours. the larger jets were to take it to the next level with the air filter and muffler opened up. my wife is considerably lighter than either of us and as a new rider she doesn't push it at all. i never rode it with the 15t sprocket. i guess load and terrain make the difference.