Wow, 35mpg..thats Waaayyy to low..
A 599 Hornet is an inline-four and gets like 36 mpg.
The old(er) ninja 250 was rated at 65-75mpg.
Where'd you get 35???
-2009 Kawasaki Ninja 250R - Current Ride
-2007 Suzuki DR650 - Sold
-2007 Kawasaki Eliminator - Sold
Haven't taken my new 250R out long enough to check the mpg yet, but I know it gets up to 70mpg from everything I've read. Are you still breaking it in and keeping the rpms under 4000? If you're running on really low revs or lugging the heck out of the engine I could see where that might seriously impact your mileage.
My V-strom didn't get great mileage until after my first tank. Something to do with breakin maybe, I don't know. If by the end of your third tank you're still getting bad mileage, take it back to the dealer to have them check it out.
35 mpg is not good. Have you verified this over several tankfulls? If so, I'd give the dealer a call. When ridden lightly (as you should during break in) you should be seeing close to 70 mpg. Even when ridden hard, it shouldn't get lower than 50 mpg.