Im thinking of picking the new 250 up this comming summer. Im 5,4 145. Should I have a problem fitting on this bike?

 

Well whats the inseam on your jeans? Usually if the inseam of your jeans is within a few inches of the bikes seat youll be able to get both feet flat on the ground no problem. I dont see the bikes seathight being more than 30" unladen. So with a person on it it will settle a few inches easy.

Edit: just checked the sight, they print the seat hight as being 30.7". But like i said it will settle a bit with wieght on it, and also i remember reading that the new 08s have adjustable rear shocks. If thats the case youll be able to have the dealer drop the hight a few inches if need be.

 

With a seat height of 30.7" static, once the rider sag was set, you should be in the comfy height that you are asking about.
Welcome to the forums jw87