So in theory can those of us with the 43cc MVVS' simply replace piston, ring, and head to have a 50cc? I have one 43 that stripped the exhuast mouting tabs and the ignition went bad (I have a new style ignition which would require me to buy a new head anyway to work with the ignition) so if I have to outlay the $$$ would be nice to build it into a 50cc...