Ok guys. New to the four stroke life. Just picked up an 09' kx250f. Has 27hrs since new. I have had it for about 2 weeks now. Bike ran great. Always started right up. Now i cant get it to start to save my life. Changed out the plug and still nothing. I have spark, its getting fuel and air. Im at a loss. Been trying to get it running for the past three days and nothing. Please help??!