As the title states, my wifes 400EX seems to be over responsive at higher speeds. As in, barely touch the bars at speed and the quad turns too fast too quickly. I'm using my Banshee as a reference, which seems a whole lot more stable at speed. The 400EX is completely stock, no modifications.

Any help would be appreciated pertaining to fixing this.

I'm thinking toe adjustment? Possibly too much air in front tires, but that seems to be a stretch.

 

Easy enough to figure out, set proper toe and play with tire pressures. I know my SxS was twitchy with toe out, reset to 3/32 -1/16. Toe in and it tracks straight as an arrow!