Did you do a search before posting this question?

Anything can be converted to anything,you could put a steam engine on an airplane if you wanted to.
Honda doesn't have problems inverted,some of the others may,any wet sump four stroke should not be run inverted.
Basicly if you plan on doing something with anything other than a 2 stroke zen your wasting your time here,because the anti four stroke crowd comes in and hijacks meaningful discussions with thier worthless drivel.
You don't see four stroke fans jumping into 2 stroke threads complaining about unburned hydro carbons pollluting atmoshpere or dirty smelly exhaust.