2012 KTM 250sx vs 2007 RM 250 comparison

[dean100yz]

Just looking at that graph makes me scoff at the powerbands of four strokes. And the lack of power compared to the 250s. It astounds me how people can possibly defend their purchase of a 250F

The problem Stu is they (250F's) go round a track faster then dyno figures show.
Power is not everything.

Yeh true point that

[citabjockey]

The other true point is that the 250F powerband requires you to run it up pas 12k rpm. Talk about stress on all those flailing parts. There is a reason that they are expensive to maintain (sometimes).

Also, the fact that a 33HP 250F matches the lap times of a 45+ hp 250 means that peek power only means so much. Now, if someone could put together a 2T engine that makes 35 or so HP but over a much wider range, and keep it light, and keep it reliable, and keep it cheap, it might end up being a faster bike for the masses!

Still, a 50HP KTM SX must be very entertaining to ride. Would love to try it sometime.

[Stusmoke]

Just looking at that graph makes me scoff at the powerbands of four strokes. And the lack of power compared to the 250s. It astounds me how people can possibly defend their purchase of a 250F

The problem Stu is they (250F's) go round a track faster then dyno figures show.
Power is not everything.

Touche.

The other true point is that the 250F powerband requires you to run it up pas 12k rpm. Talk about stress on all those flailing parts. There is a reason that they are expensive to maintain (sometimes).

Also, the fact that a 33HP 250F matches the lap times of a 45+ hp 250 means that peek power only means so much. Now, if someone could put together a 2T engine that makes 35 or so HP but over a much wider range, and keep it light, and keep it reliable, and keep it cheap, it might end up being a faster bike for the masses!

Still, a 50HP KTM SX must be very entertaining to ride. Would love to try it sometime.

In most cases yes, but look at the powerband of the 250sx; its pretty linear for a two stroke. 8500 RPM peak horsepower (by my eyes) and falling down in the RPM ranges wouldn't be a disaster. Hell all of those 250s are pretty linear. So I reckon running it like a fourstroke would keep it perfectly competitive in the power department but maintaining the light weight advantage through the corners

[Micahdogg]

I also came off of a 2001 RM250 and onto a 2011 KTM 250SX.  I have to agree with most of what was posted.  The RM was a turd down low and I would frequently stall it out while hopping logs in the trails.  I even changed gearing and added 11oz of flywheel weight and it wouldn't matter.  The RM was dead downlow, went apesh*t in the midrange, and kinda fizzled out on top.  It was a very snappy, very exciting powerband, but was a real chore to finesse around a trail quickly.

The KTM lugs hard, pulls smooth and has more on top.  It's not as exciting, until you start laying down some good laps and realize how well the power is produced.  Mine also has a knock sound, but I think it's probably due to the 93 octane I'm running.  I bet it would go away if I used something closer to 100.

The brakes are just stupid.  There is no need for this much brake.  I'm never even close to 50% effort on the front brakes.  Most of the time I just breathe on the lever and the bike stops fine.

Ergos are pretty close. 

Handling, I do feel like the RM handled better.  I only have about 25 hours on my KTM, but I feel like I have to move around more (stay up front more) in order to get comfortable in the handling.  I'm still not there, but it's not like I was always comfortable on the RM.  On more days I felt dialed on the RM's handling though.  The KTM is tolerable though.  Keep in mind I have the PDS shock too.

They hydraulic clutch is nice.  I never wanted one, and after just a few rides I like it so much that I would retrofit it to another bike that didn't have one standard.

Overall, it's a very nice bike and I have no regrets.  The powerplant felt so good stock that all I did was lean the clip one notch (to cut down on the spooge) and that's it.  I'm not even messing with needles or the PV spring. Between the motor, brakes, clutch and nice new package of the 11+ KTM, I can more than handle any negatives.

[chump6784]

I always run 98 octane but the tank of fuel in the bike came from the and I don't know what they had used. The other guys ktm had a knock sound but not as loud as mine.

One complaint. Vibration. I am surprised every woman doesn't have a ktm tucked away for those lonely nights.

[_X_]

ha!

[chump6784]

couple of pics from the weekend. didn't have the good lens on the camera so the photo's aren't zoomed in real well.

[TMKIWI]

Looks like your boy is making Brrrp Brrrp sounds.

[_X_]

seat bounce! new school front of the bike huh. look good man.

[gpnewhouse7]

Also, the fact that a 33HP 250F matches the lap times of a 45+ hp 250 means that peek power only means so much. Now, if someone could put together a 2T engine that makes 35 or so HP but over a much wider range, and keep it light, and keep it reliable, and keep it cheap, it might end up being a faster bike for the masses!

You mean like a KTM 200 exc? 

[chump6784]

seat bounce! new school front of the bike huh. look good man.

No seat bounce, just trying to soak that sucker up.

[_X_]

i try to seat bounce everything

[citabjockey]

In most cases yes, but look at the powerband of the 250sx; its pretty linear for a two stroke. 8500 RPM peak horsepower (by my eyes) and falling down in the RPM ranges wouldn't be a disaster. Hell all of those 250s are pretty linear. So I reckon running it like a fourstroke would keep it perfectly competitive in the power department but maintaining the light weight advantage through the corners

Linear is not the same thing as "flat". When you look at these dyno charts you see the linear climb of the 250's (and also -- to a much smaller extent the 250f) in the slope of the line. If someone could take a 250 motor and simply clip off this top portion -- limit it to between 35 and 40 horsepower but have it make that power starting at 4k and the same at 5k and 6k and 7k all the way up to 10k, THAT would be a flat powerband and much wider than even the spread of the 250f.



Now such an engine would not win any drag races against a 50HP SX BUT in any kind of technical stuff it would be more predictable and require less compensation by the rider to dial in exactly how much power is desired (for example, as you accelerate in a place where the tire can only stand 25HP before breaking loose you have to be backing off the throttle as the engine makes more power just by RPM). Easier to ride. Also less interesting to ride and some would say less fun as well but might end up being a faster bike for lap times -- at least at an amateur or lower levels. And because it would be stressed less than the 50HP models it should last forever.

All that said, the best riders can deal with the steep power curves and can take advantage of 15  or so extra ponies -- so the top pros would always be put on the bikes with the best power. Because of this the public will never get to sample a machine like this -- the manufacturers have no reason to build it. I do think it would be interesting to put joe average racer on it and see what would happen.