Do you think its going to be a true 300? Most manufacturers have a habit of rounding up, take the CBR300 for example, its actually 286cc....
Be prepared to see 299cc! :|I think it will be right around 300cc. If it were a bit above 300cc then I bet Yamaha would call it a r35, and if it were higher than 350cc they would call it an r4. Its always best to round up. So, I'd guess that the displacement will end up being just under 300cc.