I am running a modded 426ex and my jetting on all three circuits are pretty close. The motor runs fine all through the powerband.
The problem happens only when I slam a corner, i'm not talking cornering fast, i'm talking not letting off, hitting the berm full throttle and staying in the throttle. When I do this, the motor stumbles as if starving for full or bogged, then comes right back on fine. I don't have a float level gauge, but I do have calipers.

Has anyone ever had this problem? There has to be a fix, I should be able to rail full throttle. This one is stumping me. Thanks for the help.
Nick

 

Dude, I had the same problem with my 426ex.....Come to find out, my air intake boot that hooks my head to my carb had a crack in it.....when the bike hit hard or rollled in a turn, it suck alot air....check you entire system for leaks....make sure you air tube is well connected between your carb and air filter......Let me know if you find any leaks.....