The Ninja 250 you have is a 4 stroke 250, do you mean 4 cylinder 250? If so there is currently no 4 cylinder 250 sport bike made or sold in the United States...
anyone make still make/sell a 4 stroke 250cc sports bike in the united states? I have a ninja 250 right now and I think a 4 stroke 250 would be sweeeet. Better than upgrading to a 650 and not as fast as a 4 stroke 600.