I have a 99 YZ400F. I had it for about a year and before that it was in storage for 3 years. It always started on the first or second kick. I never had a problem starting it like others have had till last night. The bike started up on the first kick like usually after ideling for about a min I put the choke back in and the bike shut off. I was unable to start it for about 45 min. I tried everyting hot start, choke on, choke off, pushing it, etc. I had no tools with me. Has a clean air filter, and good gas. I turned off the gas line and kicked it like mad and it finally started. I dont think I flooded it? While started I turned back on the gas. It was fine for the rest of the day. First time having this problem, I will try it again tonight but does anyone have any thoughts or ideals on what to further look into.