if you take the lid off of the filter box will that do anything and is there anything i can do to make my 400ex better without spending money , how do you jet it or is there any settings i can do to the suspension engine or naything is there a a special oil that can give me more hp or spark plugs

 

the best way to gain a few horsies w/lil money is going w/the K&N Power Kit..filter,jets,cleaner..everything..its like $100...then take the baffel out of your stock exhaust!take your air box lid off...umm you could work with the suspension a little bit like for riding easier wheelies raise the front shocks up a little bit...and no changing your oil will not give you hp

 

stock shocks are adjustable, I set mine 2 from the hardest setting and noticed a HUGE difference from when I had it stiffest while jumping.

 

make sure your throttle cable is adjusted. you adjust it where your cable goes into the throttle mechanism on top of your right handlebar. adjust it so that there is about 1/4 inch of play in the throttle lever. if it isnot adjusted properly, your carb will not be fully opened when you have it pinned. if you take the airbox lid off, rejet the bike to compensate for the increased airflow. this will give a little power but nothing drastic. also, i recommend buying single individual keihin jets instead of the whole jet kit. it will be cheaper and you won't have to buy so much crap you don't need.

 

taking the baffle out of you pipe is not a good idea. it will give you a little more power but it will also burn up the motor becouse of loss of compressoin. it will not burn it up right away. you could run it for a long time like that but it will start to smoke and burn oil and then it needs rebuilt so i wouldnt recomend that

 

ya i was just about to say dont take off the baffle to

 

i have a 400EX too, y would u want 1/4 inch of play in the throttle, i thought that would make it so ur carb isn't opened all the way when u pin it. i messed with my throttle while i had the quad running and when i tightened it all the way up, it gave it more gas, it was the equivilant of barely pressing on the gas. u could hear the engine revving higher.

 

1/4 throttle is just fine. this amount of play will make the carb fully open up. when you tighten it all the way up, your idle will increase because its pulling the carb open a little big. when it is all the way tight, all it takes is for you to turn the handlebars to stretch the cable a little bit and the carb will be opening up.