hi i have a 400ex that doesnt like to idol without the choke on just a bit alsoi when it hits high rpms it wants to bog out, i have a white bros slip on exhaust with k&n filter in stock airbox with lid on. i have had this problem since i have had the bike, i am just not a carb guy and this thing gives me fits. i do know that this thing likes plugs alot dont know if thats just 400ex on not. if someone could help i would appreciate it thanks.

 

Welcome to the forum. Sounds like you're about to learn about carbs. The idling on choke issue is usually from a clogged pilot jet, as far as the bogging try taking your lid off and run it, with the exhaust and filter if it was jetted for those mods it may be running rich on top since the lid is on. And what do you mean about it liking plugs?

 

well it seems i have to change the plugs an awfull lot i never had that prob with my 230 suzuki