this is a basic big bore kit, it will turn your engine into a 184cc, and you can still use your original head etc
the carby will need rejetting, larger jets etc
http://www.dhz.com.au/buy/tb-184cc-big-bore-kit/TBW9042
basically, undo cam sprocket, cam chain, drop the exhaust, remove your head, carby and manifold, then remove your barrel and piston.
then you are ready to start fitting the new stuff,
piston, barrel, then refit your head, cam chain, manifold, carby, exhaust
and retune it to suit