We spent all day yesterday trying to start the thing and the most it did was started then it would die but would not stay running. It seems like the choke doesnt do anything but we just serviced it and honda said that it was running fine and there was nothing wrong with the choke or anything and we have had it for six months and always had a heck of a time starting it. if anyone has any helpful ideas please post them. thx

 

This motor likes fresh gas in the float bowl and slightly advanced idle for starting. With my 04 400EX I just open float drain screw on left side of float bowl until I get a steady stream of gas onto the ground. This replaces stale gas in float bowl with better gas from tank. And then if you have good fresh gas in tank it should fire up. For cold starting I give thumb a couple pumps with full choke and it always fires. If it still will not fire then you may have a plugged up pilot/idle jet. The poor gasoline quality in most locations goes bad quickly.

 

i have a 07 400ex too. also hard as hell to start.last time before i parked it i ran carb out of gas it seems to help.gas in your carb bowl might be stail. make sure you have fresh gas in your carb.so drain gas out of carb-take spark plug out and dry cylinder out so its not flooded-pull choke-pump throttle 3-4 times-should start.soon as it starts go to half choke.not good on engine to run on full choke for long.and it could use a 42 pilot jet will help cold starts. kinda easy to flood out dont pump throttle too much!!! let me know what happens

 

mine did the same thing...messed with the wires, took the choke off and no probs since!