I looked throught the recent posts pertaining to throttle adjustment but none of them seemed to fit my problem. So, my problem is my thumb throttle lever has alot of slop in it. I have replaced the cable with a new cable, but this still didn't solve my problem. thanks for your time. btw im going to st joes this weekend maybe ill see some of you out there?

 

under the rubber boot on the throttle is an adjuster for this. to adjust it it helps to take the air boot off the carb on the air box side. this is done so you can see in the carb. adjust the cable so that it will open the carb all the way and no more. alot of the 400ex's came with this out of adjustment and would not open to WOT. when I did mine the slide hung down about a 1/4 inch so it really cut the top end speed down. hope this helps. peace sickmojave

 

you can also adjust the slop by way of the carb itself, if you want to take off the plastics and tank, but on the top off the carb there is a nut on the throttle cable..same idea as the on on the lever

 

thanks