Installing a set of 18mm offset triple clamps should help a lot.
I had a set of Applied Racing clamps and I think there are some others.
The topic has been discussed many times in the past.
Do a search and you'll get more info.
Otherwise, try raising the fork legs up in the stock clamps 5-10mm and see if that helps.
What the 2 posts above said, and shorten the wheelbase. I went to a M12 rear tire which has a low profile, and allowed me to shorten the chain and move the rear axle forward. This I combined with sliding the forks up in the triple clamps 3-4mm, and I achieved a noticeable improvement.
I believe a lot of it is riding style. True, KTM's don't turn razor sharp like the newer Japanese MX bikes. I rode a YZ400 last year and this year I'm riding an '01 KTM 300 MXC and for sure the YZ cornered sharper than the KTM. The KTM is a bit lazy in the corners, but I've found that riding style plays a big part in that. My experience has shown that KTM's like a lot of throttle in the corners. I steer with the throttle a lot. The KTM's have such a smooth power delivery that you're able to get on the gas very quick in the corners and when you do that, the motorcycle will corner with anything out there.
But certainly, you can improve the handling by shortening the wheelbase and lowering the front end, as has been suggested here. I haven't tried the 18mm offset clamps, but everyone raves about them and claims that if you're willing to spend the money, that the handling will pretty much mimick a Japanese MX bike. I can't afford to buy those this year, but I've found that tweaking my riding style a hair has improved things a great deal. Good luck!
One other suggestion: you might want to play with the sag setting on the rear end. Most people run 95-100mm of sag. When I had my bike set up that way, the rear end felt too high to me, (the stink bug effect as the magazines call it). I run about four and a half inches of sag on my bike and that seemed to improve the handling as well. You suffer a little trade off with the softer preload setting, but I feel the bike corners better and the rear tire hooks up better with that much sag.
:cool: I have been riding my 400 exc since March '00, and here is what I found: per these other posts, raise your forks 7mm in the tripple clamps, set your sag at 95mm, regear to 13/50 so you can use all that marvelous power IN the turn, and then just ride your heart out, not worrying whether or not you left some iota of performance possibility untapped. The beauty of this sport is still, as it has always been, that the rider is what matters. See ya at the finish line. Good luck.
i don't think anyone mentioned changing the stock front tire, and adjusting the tire pressure according to the terrain your ridding on. I'm using the Dunlop 756 right now and it alone made a big difference. i'd also have to agree with raising the forks and the gearing as well.
shorten that wheelbase!