Whats wrong with my bike?

my bike a klr 250 has been sitting for like 7 months without being started yesterday i got the flat tire fixed and was riding it with no problems. then earlier i was heading to work got about 5 miles with no problems then i downshifted to 3rd gave it gas and all a sudden the bike was like sputtering like i was running out of gas and now my bike wont stay running for more than a second and when i give it gas its not wanting to rev and just dies....whats the likely problem is it a gunked up carb ??