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Railing the track on a 250SX

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Did a quick search and didn't find much, point me the right way if this is a repeat post...

Recently made the switch from a 250F two a 250 two stroke. 2007 KTM 250SX and I gotta say, I love the power and the weight. But I've never ridden a two stroke on the MX track before (GASP!) and trying to get the most out of it is presenting a challenge to me. It has great power, so I'm trying to get used to that. It is also very "busy" which I know is a two stroke trait.

I feel great on the bike and its a TON of fun, but my corners are suffering. I know this has a lot to do with the way a two stroke makes and delivers this power, but I can't really seem to get it to blast out of turns like my 250F. Should I be basically WFO with the throttle a lot of the time and clutch it a LOT to stay on the pipe? The hydraulic clutch on this beast is a joy and I hear you can really punish it and not worry much about it.

Thoughts? Tips? Suggestions? Thanks!

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Did a quick search and didn't find much, point me the right way if this is a repeat post...

Recently made the switch from a 250F two a 250 two stroke. 2007 KTM 250SX and I gotta say, I love the power and the weight. But I've never ridden a two stroke on the MX track before (GASP!) and trying to get the most out of it is presenting a challenge to me. It has great power, so I'm trying to get used to that. It is also very "busy" which I know is a two stroke trait.

I feel great on the bike and its a TON of fun, but my corners are suffering. I know this has a lot to do with the way a two stroke makes and delivers this power, but I can't really seem to get it to blast out of turns like my 250F. Should I be basically WFO with the throttle a lot of the time and clutch it a LOT to stay on the pipe? The hydraulic clutch on this beast is a joy and I hear you can really punish it and not worry much about it.

Thoughts? Tips? Suggestions? Thanks!

You need to have better throttle control on the 2 S and always nip the clutch as you begin to exit the corner. This nip of the clutch will make the power come on just how you want it to.

Here's somemore info on the subject;

Ever since sometime in the early 80s two strokes have put to good use the development of a power valve in the exhaust port. This power valve has smoothed out the hit of the two stroke’s power band a great deal. But in order to get a lot of horsepower out of that two stoke engine they still have a certain amount of hit to the power band. This is the biggest difference between the two and four stroke. The four stroke is just smooth tractor like power right off idle all the way upstairs. This is why the four strokes depend less on the clutch and more on throttle control. You don’t have to help it into the power with the clutch nearly as much as with the two strokes.

The other difference is with engine braking. When you’re going down a straight away and you shut off the throttle on a two stroke the back pressure from the engine will slow you down a little, but on the four stroke this engine braking is much stronger. This will make the Exit Dex of a corner (where you go from braking to accelerating) easier. You don’t have to be quite as precise with the brakes. This engine braking effect will affect you on jumps too because if you roll the throttle off on the take off of a jump it will throw the front end down much more on a four stroke. This won’t be as noticeable if you’re in a higher gear.

Since you don’t have to be as precise with the clutch and throttle and the brakes on a 4 stroke they are easier to ride.

At this point in time that’s the main differences between the 2 and 4 strokers. The actually riding techniques are the same. The way I see it it’s all good.

All the details for the clutch, throttle and shifting techniques are shown in this DVD, see a free preview here; http://wp.gsmxs.com/dvd-3-clutch-throttle-clutch-control/

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Thanks for the reply! I'm having a blast on it, just quite a transition. I bet it's weird to hear about people that are making a 4t -> 2t transition, not the other way around.

Gotta say, love the brakes on this bike! Bremboooooo...

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Thanks for the reply! I'm having a blast on it, just quite a transition. I bet it's weird to hear about people that are making a 4t -> 2t transition, not the other way around.

Gotta say, love the brakes on this bike! Bremboooooo...

not really. around here there are lots of guys switching to 2t's for the fun factor, lower maint costs and reliability. :busted:

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Its a huge exodus here in California as well. Every day I see more and more pumpkin 2 strokes on the track, especially 2012 models. KTM has done a great job building and marketing these new 2012 MX 2 strokes to the point of being completely sold out in the US. New shipments aren't expected until a few months into 2012.

Its funny, I can get on pretty much any bike, 2 stroke, 4 stroke and ride it just as well as the other. Most of that comes from learning on a 125 and I personally feel once you can ride a 125 quick, everything else is a quick adjustment of the mind set and you're good to go!

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I have switched to a 250SX in the summer after 5 years on 4-strokes and I know how you feel. What has helped me most was playing with bike setup. Get the KTM handlebar switch for the ignition mapping and try all powervalve springs. Basically, you want to get that bike's power snappy but not overwhelming. Also, set the sag to get the wheelspin just right, not too much but enough so the bike doesn't wheelie on you (too much).

Last, keep one finger on the clutch at all times. When you start pushing that bike it will try to get away from you, and it will if you don't pull the clutch in time.

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Yeah riding out in the desert this past weekend I learned about basically opening the throttle and fanning the clutch. Seemed to work, headed back to the track this weekend to check it out. Sag is set, but I think the most important thing right now is getting the suspension dialed. It's sprung for desert and a guy that's 145 w/gear, and I do MX and weigh about 180 with gear. We added fork oil to compensate and the sag is currently right, but it could be a LOT better.

Just curious about the basic method so I can practice correctly when it is finally dialed in.

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With regards to cornering, visualize yourself maintaining momentum and carving smooth lines on the power through corners rather than exploding on exit. It will make the roost you seek more approachable.

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nice! braaaaaaaaap. i was a lot faster at the track this weekend, but now having speed, i have approached the limits of this patchwork suspension. ordering new (fancy!) SMART performance bits this week for it. Proper suspension. Win!

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on my 2011 250 sx i used the green spring and went 1 tooth larger in rear and added an fmf shorty. i am not that fast so i wanted to tame the hit and get more grunt out of corners. it feels like a 3 stroke now. not as pipey/punchy as before. if you are a good rider then i have read the magazines like the procircuit pipe/silencer and red spring.

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May help if you see some people riding 2 strokes, May or may not help but still really cool videos

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That second video should be required viewing for anyone making the switch to a 2T. Love it!

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