Kx 450sr vs ktm 350

450 for fast guys racing

350 for needing more than a 250

250 for all the rest 

jmo

Very different bikes. A 450 needs better throttle control and takes more strength and energy, your 350 is much easier to ride and more forgiving. 450s can be mapped to be way smoother and easier to ride, but most don’t come from the factory that way. 

What kind of rider are you? Do you like to torque your way around in taller gears or rev the bike more? I’ve got a newbie friend who has a 350 and I think he’d be better off on a smooth 450 cause he doesn’t like to rev the bike, all that top end pull goes untouched.

hope that helps, it’s really a question about you more than the bike 

350 is just more fun, that’s all

the 350 has the best mapping released to public IMO

I’d like to ride Kawi (the SR looks awesome), but the 350 really is the sweet spot for a lot of us.

Until a Jap manufacturer makes one, l’ll probably ride Austrian

For me it was the exact opposite. The 250 and 450 where more fun and the 350 was lacking.

Most of the moto folks saying the 350 is the bee's knees are really fast or really slow. The guys in the middle sell them after buying the hype. Ride one for yourself. What rider group do you fall into?

You need to give more details.  Are you racing or just riding?  How big are you?  How fast are you?  
For me, if I was just riding (or trail riding/racing), I’d probably stick with what you have if you’re happy with it.  If you’re racing MX and you’re on the bigger or heavier side, you might appreciate the added grunt of the 450.  In racing, the easiest place to make up time is between the starting line and the first turn.  I race the best attended MX series in the nation every summer, and while I see people ranting and raving about 350s here on the forum, I never see them on the starting line.  Both bikes are great, so you just need to figure out what is important to you.

The 450 KXF has the same kind of smooth power engine than the KTM 350. Both bike are great.

Um, No. The KX makes 14HP more at 5800RPM, 10HP more @7K and the same HP as the 350 does @10K. Both smooth, yes. The same? Not even close.

^ 2016? Are the numbers much different now?

The Kx450 is very smooth 

The KX picked up a bit of over-rev @ 10K with the finger head. Not too many guys riding 450's on the back side of the power curve WFO. Not the same dyno so the peak numbers differ but you get the picture.