You don't say which one you have...! but have you check the breather pipe..?
Engine Uses Excessive Amount of Oil
1. Incorrect oil viscosity/type.
2. Clogged or improperly assembled breather.
3. Breather reed broken.
4. Worn or broken piston rings. no sir i dont know about breather pipe??? it's a vert.shaft 1 cyl.oh valves
5. Worn cylinder bore.
6. Worn valve stems/valve guides.
7. Crankcase overfilled.
8. Blown head gasket/overheated.