KX250F Vs 250SXF

How close can a 250f come to a 350f in power and still be reliable? I’ve got a 17.5 250f and want a 350f really, really bad.

Not sure what the dyno figures are but my mates 250sxf with everything done feels just as fast if not faster in some places than my stock 350. The part I really love about it is, its bit easier to put it where you want it and corners much better. Thats the whole reason of me wanting to go down that path.

Double wrote:

Not sure what the dyno figures are but my mates 250sxf with everything done feels just as fast if not faster in some places than my stock 350. The part I really love about it is, its bit easier to put it where you want it and corners much better. Thats the whole reason of me wanting to go down that path.

They only feel faster because of the gearing. Go up two teeth on the rear of your 350 if you want some more snap. A 350 will go 10mph faster, or more, in third than a 250..

T-Fish wrote:

How close can a 250f come to a 350f in power and still be reliable? I’ve got a 17.5 250f and want a 350f really, really bad.

My 250F from Twisted Development has high comp piston, ported head and Vortex ECU. It’s close to a 350 but feels lighter. 350 still has more bottom end. I’ll get About 40hours, maybe 45 at 30+ speed, per top end but the 350 can go 100hours easy they say.

I went from a 14 kx250f to a 17 350 sxf And wouldn’t look back.
I have always liked Kawi, but wanted more grunt and a reliable bike. I’m just not a 450 guy. I’ve tried to like it but not for me. Maybe later in life that’ll change, haha. So this brought me to the 350.
Cornering- I about ate it the first corner I hit at speed after spending those years on the KX. The KTM corners a lot different than the KX. I prefer the KTM.
Suspension- I honestly liked the Kawi suspension once I had it revalved. I rode a buddies stock Suspension vs mine back to back and noticed a big difference in how it soaked up the small stuff. I rode it stock for a couple rides after setting it up for my weight and it wasn’t bad, just not quite where I wanted it. Your on a KTM so you know all about the Suspension.
Motor- I will say that year KX had a pretty strong motor. I’d run the aggressive coupler pretty much the entire time. I’ve ridden newer ones and didn’t feel quite as strong. Newer YZ250f feel similar, in my opinion anyways. I did have issues with the secondary injector, just pulled it off, hooked it up to a battery and sprayed brake cleaner through it. Good to go. I’ve always thought Kawis were fairly easy to work on. Had to shim valves a bit. Great bike, like I said just wanted more grunt. The 350 was everything I was looking for, a big 250f.
Is your 350 modded? I went up two teeth in rear, fmf 4.1 Ti slip on and different throttle cam and it’s perfect.

Also I’ve ridden the Kx and sxf back to back. The Kawi has lots of power, great overall engine. I didn’t like the fork and the bars/cockpit feels high compared to KTM. Estart in KTM is awesome, I love the overall package

It’s very doubtful that your friends modded 250f is pushing 54hp or more.

Sounds like you're looking for more over-rev. Have it remapped if it's stock. Could save you a large amount of money if you find some simple mods for your 350. A modded 250 is a money pit...

I’m saving for a 18 or 19 KX250F right now. I have a 450, and really like that bike. But every time I ride a 250F I have so much fun on it. And I definitely feel like I can ride it faster and for longer. I’m partial to the Kawi because they feel so good for tall riders, and I can get one really cheap. That and I’m used to my 16 KX450F already.

My plan is just suspension revalve and a pipe. Stock otherwise.

JBecker 72 wrote:

I’m saving for a 18 or 19 KX250F right now. I have a 450, and really like that bike. But every time I ride a 250F I have so much fun on it. And I definitely feel like I can ride it faster and for longer. I’m partial to the Kawi because they feel so good for tall riders, and I can get one really cheap. That and I’m used to my 16 KX450F already.

My plan is just suspension revalve and a pipe. Stock otherwise.

The local Yamaha / Kawasaki shop I used to work at still takes care of me, even though I'm a 38 year old washed up / never was racer. Since i got cost on parts I went all Yamaha; 04 YZ 250, 09 YZ 250f, and recently added a 17 YZ 250X smoker. One day I will buy another 250f, and while I love the Yamaha forks and quality, the KX250f can be bought way cheaper (Kawasaki is much more friendly to the dealer than Yamaha is) and it's slimmer than the Yamaha. Since I have a few bikes I don't put a whole lot of hrs on them anyway, and I have been thinking about picking up a left over KX250f when the time comes. I just need to ride one first to make sure I don't hate it. I like my 09 YZ 250f a lot, a new KX250f has to be better than my current 250f, correct?

JBecker 72 wrote:

I’m saving for a 18 or 19 KX250F right now. I have a 450, and really like that bike. But every time I ride a 250F I have so much fun on it. And I definitely feel like I can ride it faster and for longer. I’m partial to the Kawi because they feel so good for tall riders, and I can get one really cheap. That and I’m used to my 16 KX450F already.

My plan is just suspension revalve and a pipe. Stock otherwise.

flopper12 wrote:

The local Yamaha / Kawasaki shop I used to work at still takes care of me, even though I'm a 38 year old washed up / never was racer. Since i got cost on parts I went all Yamaha; 04 YZ 250, 09 YZ 250f, and recently added a 17 YZ 250X smoker. One day I will buy another 250f, and while I love the Yamaha forks and quality, the KX250f can be bought way cheaper (Kawasaki is much more friendly to the dealer than Yamaha is) and it's slimmer than the Yamaha. Since I have a few bikes I don't put a whole lot of hrs on them anyway, and I have been thinking about picking up a left over KX250f when the time comes. I just need to ride one first to make sure I don't hate it. I like my 09 YZ 250f a lot, a new KX250f has to be better than my current 250f, correct?

Any of the new fuel injected 250Fs are so much nicer than the carbureted bikes. A little more hp and silky smooth throttle. Not having to worry about that bog on g outs makes a huge difference.