best thing you could do is take it apart, give it a good polish, take the sharp edges out of the cylinder, polish the piston, crank, lube up all the bearings, loctite all the Hex Bolts, JB weld the Petcock and install a fuel shutoff valve, cut 1/8" off the tip of the reed plates and rework the arch, cut half the fins off your flywheel and polish it, regap the coil to .020"(about the width of two normal buisness cards), regap the spark plug to .030", Measure the squish and adjust it, use yamabond as your head gasket.
^^^^^
there are tutorials to do all of this available in
air cooled pocket bike section, check out the
how to's aswell.
Your better off taking the time to make the bike reliable, instead of ruining what you have and having to replace a bunch of parts. Plus, this will let you get comfortable with the engines, and facilitate any replacements/performance upgrades you might do in the future.