Thx for the reply..my rpm nvr goes over 6..it be stuck at rpm 5-6 at speed of 100..maybe a little more if its a downhill.if its a uphill,had to kick down to gear 5 or it will kind of loss power and went down to 80.just did normal servicing..have not service carb yet and have not tell any mech of my prob cuz i noe how easily i can get fool by dem by tellin me all kind of bullshits..so decide to find out a little bit more before i go to any mech..My sprocket size is 35/36 if im not wrong.