Ultimate KTM 2-stroke

burn1986
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burn1986
Edited Date/Time 4/30/2013 4:28pm
Pretty good read by MXA on modifying the 2012 KTM 250SX. The main issue for this bike has always been the WP suspension. I wonder why they couldn't just put some YZ250 forks and shock on it. The SSS suspension is some of the best. Anyway, http://www.motocrossactionmag.com/Main/News/HOW-TO-BUILD-THE-ULTIMATE-K…
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nytsmaC
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nytsmaC 4/29/2013 10:45am
4/29/2013 10:45am
The front fender doesn't ruin the whole bike for you?
queen of spodes 4/29/2013 10:56am
4/29/2013 10:56am
nytsmaC wrote:
The front fender doesn't ruin the whole bike for you?
We looking at a different bike? What's wrong with the front fender?
nytsmaC
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nytsmaC 4/29/2013 11:00am
4/29/2013 11:00am
nytsmaC wrote:
The front fender doesn't ruin the whole bike for you?
queen of spodes wrote:
We looking at a different bike? What's wrong with the front fender?
Nothing, just that the OP is obsessed with them.
burn1986
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burn1986 4/29/2013 11:52am
4/29/2013 11:52am
nytsmaC wrote:
The front fender doesn't ruin the whole bike for you?
HA HA! Yeah, it's definitely a factor. Why can't they try one of the Acerbis fenders or retro fit a TM fender or Beta? LOL

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Lightning78
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Lightning78 4/29/2013 1:07pm
4/29/2013 1:07pm
I rode a '13 250sx yesterday at elsinore..... My steed of choice is an 06 RM250 so i had been putting laps on my RM and this guy let me ride his brand new 250sx. 2 things stood out to me, to my surprise it handled a lot better than my RM which I didnt think was possible and the brakes were awesome!!! Now I have realized my brakes need some work or an oversized rotor because there was no comparison.

One thing that shocked me was that my RM was a LOT faster than the KTM which makes 5 more horsepower than my RM? I only have a v-force and a fmf system. I even went to a 1 tooth smaller rear sprocket on the RM and it still will out yank the KTM by a mile. It picked up clean in the mid and had a decent top but my RM could walk all over it. Again that was surprising to me.... Suspension was decent and plush and the ergonomics of the bike were spot on.....that hydor clutch was pure butter too.
Shawn142
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Shawn142 4/29/2013 1:19pm
4/29/2013 1:19pm
The 250SX is very dead on top.. at least the stock '12 I rode was. It really needs the pipe and silencer to open things up. It didn't feel anywhere near the hp rating KTM claims because it all comes on and vanishes so fast.
yota
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yota 4/29/2013 1:29pm
4/29/2013 1:29pm
Shawn142 wrote:
The 250SX is very dead on top.. at least the stock '12 I rode was. It really needs the pipe and silencer to open things up...
The 250SX is very dead on top.. at least the stock '12 I rode was. It really needs the pipe and silencer to open things up. It didn't feel anywhere near the hp rating KTM claims because it all comes on and vanishes so fast.
It really only needs the PC silencer to wake up the top end. IMO.
cablecable 4/29/2013 1:36pm
4/29/2013 1:36pm
Lightning78 wrote:
I rode a '13 250sx yesterday at elsinore..... My steed of choice is an 06 RM250 so i had been putting laps on my RM and...
I rode a '13 250sx yesterday at elsinore..... My steed of choice is an 06 RM250 so i had been putting laps on my RM and this guy let me ride his brand new 250sx. 2 things stood out to me, to my surprise it handled a lot better than my RM which I didnt think was possible and the brakes were awesome!!! Now I have realized my brakes need some work or an oversized rotor because there was no comparison.

One thing that shocked me was that my RM was a LOT faster than the KTM which makes 5 more horsepower than my RM? I only have a v-force and a fmf system. I even went to a 1 tooth smaller rear sprocket on the RM and it still will out yank the KTM by a mile. It picked up clean in the mid and had a decent top but my RM could walk all over it. Again that was surprising to me.... Suspension was decent and plush and the ergonomics of the bike were spot on.....that hydor clutch was pure butter too.
are you kidding you must be the worst test rider on planet earth I've ridden both and the ktm shits on the rm so hard in the motor department
hellion
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hellion 4/29/2013 1:54pm
4/29/2013 1:54pm
There are so many variables here, but for starters the KTM comes jetted pretty badly. Just fixing that can really wake it up, and the 13's seem to be responding to some pretty big main jets (not sure why as my 12 didn't respond similarly). Then you have the power valve spring which can be swapped and the preload on that spring also adjusted. My guess is that the KTM you rode was poorly set up, because they are rockets in my experience.
mxtech1
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mxtech1 4/29/2013 2:44pm
4/29/2013 2:44pm
The KTM motors is much better than the RM motor. It's all in the way the KTM motor delivers the power. It's smooth from the bottom to the top and doesn't have the massive hit like the RM does.
ob
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ob 4/29/2013 2:46pm
4/29/2013 2:46pm
Also, I think the heavy flywheel the new ktms use make them feel slow. They are trying to make them more tractable. I have a 13. They definatly need to be re jetted before you let your buddies ride one.
Lightning78
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Lightning78 4/30/2013 10:13am
4/30/2013 10:13am
Lightning78 wrote:
I rode a '13 250sx yesterday at elsinore..... My steed of choice is an 06 RM250 so i had been putting laps on my RM and...
I rode a '13 250sx yesterday at elsinore..... My steed of choice is an 06 RM250 so i had been putting laps on my RM and this guy let me ride his brand new 250sx. 2 things stood out to me, to my surprise it handled a lot better than my RM which I didnt think was possible and the brakes were awesome!!! Now I have realized my brakes need some work or an oversized rotor because there was no comparison.

One thing that shocked me was that my RM was a LOT faster than the KTM which makes 5 more horsepower than my RM? I only have a v-force and a fmf system. I even went to a 1 tooth smaller rear sprocket on the RM and it still will out yank the KTM by a mile. It picked up clean in the mid and had a decent top but my RM could walk all over it. Again that was surprising to me.... Suspension was decent and plush and the ergonomics of the bike were spot on.....that hydor clutch was pure butter too.
cablecable wrote:
are you kidding you must be the worst test rider on planet earth I've ridden both and the ktm shits on the rm so hard in...
are you kidding you must be the worst test rider on planet earth I've ridden both and the ktm shits on the rm so hard in the motor department
Hey i dont disagree with you I was equally shocked but I rode the bikes back to back 2 times and I swear the rm has more explosive power and gets to the turn faster ....at least mine does, maybe he had his bike a little rich? I dont know but it was MUCh slower....seat of the pants impression and I know what im doing on a bike. I am no shitty test rider.
mnomis484
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mnomis484 4/30/2013 10:43am
4/30/2013 10:43am
would have been better to do the same to a 2011 model, because they have got no linkage (still pds). it is easier to maintain, weights less than linkage and the mxa test riders said, that they didnt feel a big difference between the 2011 250 2 stroke (pds) and the 2012 250 2 stroke (linkage) except the added weight.

other than that, the 2011 is completely the same except the reed cage.
What
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What 4/30/2013 11:55am
4/30/2013 11:55am
mnomis484 wrote:
would have been better to do the same to a 2011 model, because they have got no linkage (still pds). it is easier to maintain, weights...
would have been better to do the same to a 2011 model, because they have got no linkage (still pds). it is easier to maintain, weights less than linkage and the mxa test riders said, that they didnt feel a big difference between the 2011 250 2 stroke (pds) and the 2012 250 2 stroke (linkage) except the added weight.

other than that, the 2011 is completely the same except the reed cage.
The 2011 model's airbox does not have to snake around a center mounted shock, therefore it makes more power. Also, KTM changed their ignition for 2012 and it's supposedly not as good as the 11. But yes, if I were building a KTM it would be an 11, with 13 shrouds and KYB SSS forks of a Yamaha 250F (so you get the stiffer springs already installed)
PPS Moto
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PPS Moto 4/30/2013 12:31pm
4/30/2013 12:31pm
mnomis484 wrote:
would have been better to do the same to a 2011 model, because they have got no linkage (still pds). it is easier to maintain, weights...
would have been better to do the same to a 2011 model, because they have got no linkage (still pds). it is easier to maintain, weights less than linkage and the mxa test riders said, that they didnt feel a big difference between the 2011 250 2 stroke (pds) and the 2012 250 2 stroke (linkage) except the added weight.

other than that, the 2011 is completely the same except the reed cage.
I agree, I really want to build an "ultimate" '11 for myself, I haven't really seen one anywhere close to me worth buying though.
twosmoke30 4/30/2013 1:12pm
4/30/2013 1:12pm
expect to see something similar this summer

but with wp works suspension
fmf components
rekluse
yada yada yada

oh and some points being scored to back all this up
Lightning78
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Lightning78 4/30/2013 3:47pm
4/30/2013 3:47pm
mxtech1 wrote:
The KTM motors is much better than the RM motor. It's all in the way the KTM motor delivers the power. It's smooth from the bottom...
The KTM motors is much better than the RM motor. It's all in the way the KTM motor delivers the power. It's smooth from the bottom to the top and doesn't have the massive hit like the RM does.
I had trouble getting it going out of turn even with a stab or two of the clutch.....I think since it was brand new-ish, the jetting was way too rich, it ran like an 02 cr250 off the bottom....well throught the entire range. I guarantee you the RM can get to any point faster than THAT particular KTM ran. It was just how the bike was or maybe it was torquey and felt slow but I really had to work the bike to get over jumps the way I normally do ..... I would open it up and get over a jump with ease but with the RM I would come pinned out pf a corner carrying way too much speed, shut off early and since im 6'3, soak up the lift from the jump with my legs to stay low, on the ktm it was just throttle from the turn to the jump......any body english I used to stay low meant I would come up short every time and it was a power issue not a suspension issue.
mynewcr250
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mynewcr250 4/30/2013 4:28pm
4/30/2013 4:28pm Edited Date/Time 4/30/2013 4:44pm
the stock exhaust sucks

the stock jetting sucks

the ktm motor is no joke. i mean it doesnt make 20hp more than your RM, but you shouldnt be here calling it slow. if you told me they were even, then id have no issue as not everyone is going to feel a 3-4hp difference. setup issue IMO.

BTW anything other than the red spring with the PROPER dolly spring tension (IE: turning the adjuster flush is a BAD thing) lowers power. the ktm comes stock with the yellow spring which doesnt allow full power and creates a more linear feel. reference these torque graphs from JD jetting. pulled this off of ktmtalk

if you want an accurate comparison between your RM and the KTM you need to get rid of the exhaust, correct the jetting, and install the red spring.

blue line = red spring
black line = yellow spring (wont allow the bike to build max power but stays more linear... for a 2 stroke anyways)
green line = green spring (again, less power, even more linear feel, less "hit")
red line = red spring with the adjuster turned out closer to flush (you can see the drop in torque before it falls inline with what the red spring is suppose to do. this gives the the illusion of more power due to the pronounced "hit". this is why ktm says to not mess with the dolly screw, because it does in fact decrease performance from what they intended)

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