Levers to high

 

Agree.

If not you can get softer (organic) brake pads via KTM's Power Part program. I recently changed the sintered OEM pads against the organic ones and they require much more force on the pedal to lock the rear. Maybe worth a try...

 

Technique. To be fair, you're probably not going fast enough to use the rear brake without pulling in the clutch and you probably don't have enough skill to use the rear brake with any finesse, it'll come with practice. If you're getting up on the tank (as you should) but you're still on the rear brake then it's going to lock up anyway. You're probably not using enough front brake so relying on the rear and therefore trying to get it to do too much.

 

Just need to change your riding style a little probably? Could be clutch drag but more like as said not getting the clutch in early enough? Practice brake slide turns a bit.

 

Agree with first comments , but I had an old 98 200exc which had horrendous rear braking , turned out to be badly corroded & worn slide pins on the caliper causing it rock when putting anymore than very soft pressure on the lever it used to lock up the rear like no other bike I've owned .

 

Best way is as follows, works every time:
come in fast as f*ck
stamp on the rear brake to do a massive skid
clutch in whilst skidding
throttle pinned for the length of the skid
slide the back round the corner with the wheel locked
dump the clutch when pointing in the right direction with Wide-Open-Throttle
wheelie out with the rear still sliding

Should end up looking like this