I have a 400ex and sometimes the bike is hard to start and once it starts if you give it gas it shuts off then there are times the bike runs like it should then acts like it's not getting enough gas I have cleaned the carb made sure jets were clean and clear blew air through the carb to make sure no junk was in the passages what could be the problem any help is welcomed. Thanks in advance

 

I'd check the tank vent and petcock and ensure there is a steady stream of fuel coming down from the tank (disconnect fuel line going into carb and have appropriate container to catch the fuel. If that all checks out I'd validate your carb float is functioning properly (re-attach fuel line & remove bowl - operate float manually to ensure fuel is getting to bowl and float needle is not getting stuck. If all good there I'd move on to valve clearance and cylinder compression...

 

Thank you I'll have to dig in to it again I hope it something simple