My trx250ex wont start, been say for a while and battery had gone. Ive put a new battery in although still wont start, it starts with easy start (but cuts out after 1-2 seconds) and ive tried cleaning the carb with some carb cleaner whilst on the bike. Has spark, has fuel in (and is turned on). The carb seems to be getting fuel from the tank as it comes out when the pipe is disconnected. Is this just a blocked carb problem?