Hi there, I've been having a problem with my Yamaha Cs50 Jog r scooter what is happening is sometimes when I ride it it's absolutely fine but some days I will come to go somewhere and it runs but you can tell the difference (Lack in performance) I don't know what this is I was wondering if it was maybe that the automatic choke has a problem or maybe the problem is the carburettor. I'm not really sure but this is very annoying... I'm hoping someone can help me out on this one, Thanks