make sure your chain isn't dead (o ring chains...) and the wear on your sprockets, which is bad. yes. and also make sure your chain if its in good shape is tight enough...
change your engine oil and drain the gas in the gastank (gas begins to gell up after 75 days, and could reallly f*ck your motor up if its been sitting a long time)
check your wires to make sure nothing got hungry and decided to chew them.. especially the wires to say your killswitch.. and such..
it'd be a pretty good idea once you do all this to re-adjust your carb (turn in the air/fuel [the little brass screw on the carb] all the way in, but not too tight becuz the screw seat is soft aluminum and will get damaged.., and then back it out 1 and 1/2 turns - 2 turns or whatever your blaster may require, its different in most, especially based on temperature and elevation.]
i can't think of anything else right now besides to clean your air filter and carbeurator