if you check the stickied thread about jetting theres some plug reading links there, right now yer leaving too lil info to help you, how does the machine react in diffrent situations? how does the plugs look ?, what jets are you running?, what needle ?, how many turn on the airscrew. so far it can be alot of things you have to rule em out 1 by 1
cant tell for sure where its located on your bike but its usually a pretty tiny brass screw towards the intake part on the gas inlet pipe side of the carb