Hello! I’m new to bikes and bought a used 2012 CBR 250r from a buddy of mine so I know it was fine when I got it. Rode it a couple months then all of a sudden it just doesn’t want to shift past 4th. When I go to rise the shifter it just doesn’t budge. Thankfully I only use it around town so I never need to go much faster, but I have needed to before so I’m just wondering what’s going on. Thanks!