So I went to the KTM demo day at Glen Helen yesterday. Test rode the 6 2013 MX bikes. I am an off-roader, not MX rider and not a racer, but i just wanted to ride some new KTMs and see how they felt compared to my old KTM 380s.
The bikes there were the 125SX, 150SX and 250SX 2-strokes and the 250SX-F, 350SX-F and 450SX-F 4-strokes. You get a punch card and get to ride each bikes once. After you have ridden each bike you get a bonus ride on one bike you want a second ride on.
I switched back and fourth 2-stroke to 4-stroke to compare. Quick review: The 250F was easiest to ride (obviously) as it was least powerful with smooth 4-stroke powerband and fairly low weight. It did not have enough snap to it though and could use a little more power in the hills at Glen Helen. The 125 was awesome. It had the snap the 250F didn't have. Nothing beats the feal of a 2-stroke on the pipe. The 125 was super light and fun. The low power of the 125 made it easy to wring its neck without getting tired, but still had that 2-stroke snap. The 150 was like a peaky 125 actually. It had more power but was all top end. I am sure a head mod or pipe would fix that quickly to make it a hod rod 125. The 350F was my favorite 4-stroke. It had the power missing from the 250F but not too much that it wanted to kill you like the 450 and didn't have the 450's weight. The 450, like I said, was too much weight and power for me on a MX track. It would probably be fine in the desert.
Lastly the 250SX. This is the bike (and the 125) that I came to ride. I did my bonus ride on the 250SX as well. I figured as it is 13 years newer than my 380 it would be nearing it in power output but with the newer chassis and suspension. Well, I was disappointed. It was peaky, much like you would expect from a 125. it had considerably more power, but was still peaky. This is worse because you have to keep it in the powerband to go but with that much power on tap it wears you out. There is no lugging it or going easy. It is all or nothing.
In conclusion, nothing matches the 380 engine. It lugs down low like a ported 300 and pulls strong through the mid range to the top end. It has power everywhere. It blows a 450 away in shear power everywhere, yet has so much torque you can take it easy and lug it around. The 250SX felt down 5-10hp compared to the 380.
I bet a 200 would improve on the awesome 125 with more low end. The 300 is the best KTM (other than the 380) that I have ridden, plentiful power from bottom to top, just without monstorous amounts like the 380.
If you want an engine with loads of power everywhere that can out pull a 450F or even a 500F yet is tame and controlled when you want it, the 380 is that engine. So KTM just needs a new 380, but with the low vibrations and quiet idle of the new bikes. And DI of course.