It all boils down to geometry. Swap in a set of 22mm triple clamps and crank up the preload on the back end, maybe drop the TCs and its an entirely different beast. KTMs run 20 and 22mm TCs, for the most part anyway. Most Yamahas are 25mm.
Not quite that easy
It was an accepted problem on that generation of Yamaha with no solution (i tried everything and so did many others ) - Some of the grumblings on the AMA SX/MX side of things is that is why the Yammy's werent widely accepted bikes for the privateers either for years - until of course, the 2014 dropped with 60 hp stock --- for an AMA pro, not having to spend 10,000 bucks on the motor out of the box erases some of the pain of a "neutral handling" machine --- now all the locals seem to want a taste of the blue machine
I gotta admit, i'm very intrigued -- and for my style of racing, i like the 250 FX too--------- if there are some easy fixes to help the current generation machines stick a rut and hold its line in the turns, i may be all in