2008 KTM 144SX vs. KTM 250F

By: Nick Thompson

Chances are if you’re reading this comparison you are wondering the same as I was: How does a KTM 144 SX 2-stroke stack up to a 250F 4-stroke?

Well, 2WheelTimes.com has you covered. We help answer some questions about these two very different rides. For anyone who can’t keep up with KTM’s always-changing model lineups, the SX lines are California Red sticker closed course motocross/supercross style bikes. With that said, an off-road comparison section has been added for anyone who is considering one of these bikes for the trail. To keep things the most comparable the KTM 250 SX-F was chosen for this comparison but most any of the current 250F's would have similar results.

Let’s start with some basic specs. Both bikes are 2008 models. Side note: For 2009, KTM changed the model name of the 144 SX to a 150 SX. The displacement is no different. Both bikes use WP suspension; closed cartridge 48mm forks up front and a PDS link-less shock out back. Both the 144 SX and 250F have Brembo brakes. The 250F also has a Brembo clutch while the 144 has a Magura; both are hydraulic. Both bikes have chrome-moly frames.  According to KTM the 144 weighs in at 200.4 lbs. wet without any fuel. The 250F comes in at 212.7lbs. wet without any fuel.

Now that we’ve got that out of the way lets get to the point, ride time!!! Two different tracks were chosen to display how each bike performs in various circumstances. One track was an all-flat, tighter, more supercross-style track; the other being closer to a typical outdoor track with elevation changes and less jumps. Besides the differences in engines, the first thing I noticed was the weight difference. It is obvious the 144 SX is lighter on paper and you definitely feel it on the track. The extra inertia of the 250F’s four-stroke engine and heavier crank also contributes to the heavier feel. It’s not that the 250F is heavy it’s just the 144 is feathery light!

Entering corners on the 144 SX kept a smile on my face all day. The bike can be laid down in a corner with almost no effort; the 250F doesn’t share that same characteristic. It was also easier to keep the bike laid over under power when exiting corners. The 250F was prone to stand up when applying throttle although that can be an advantage in many circumstances. It seemed to me in corners where you could carry momentum the 144 shined but corners you would square off the 250F stayed more planted; this allowed me to be under control and get that sling-shot effect driving out of a tight corner. When jumping, the 144 is definitely more flickable, allowing you to manhandle the bike with ease.  Again, because of the actual weight and the extra inertia of the engine, the 250F didn’t “float” through the air effortlessly like the 144. Anyone trying to perfect a knarly whip might want to throw a leg over the 144.

When it came to the engines, the bikes could not be more different. In tighter corners where you can’t carry speed, the torque of the 250F engine made it much easier to regain momentum. Jumps that directly followed corners were easier to hit on the 250F as well. Since the four-stroke engine has a smoother, broader powerband I felt more confident anticipating what the bike was going to do. On the other hand, the 2-stroke has to be ridden within about a 2,000-RPM range requiring much more precision. On jumps that required very little margin for error to land safely on the backside this was especially true. I had to roll through one triple in particular many times because I couldn’t carry enough speed through the corner. The up-hills were also favored by me when I was on the 250F. The 144 could pull the hills no problem but the power did taper off once you clicked fourth gear whereas the 250F still had the grunt to keep pulling. The 144’s engine feels like it has plenty of horsepower on top to compete with the 250F but obviously lacks major low end power compared to the four-stroke. You can get away with being in the wrong gear from time to time on the 250F, not the case on the 144. If you’re in the wrong gear you’ll know it instantly. The 250F makes enough torque to pull you through to all your horsepower up top. You had better already be in the “meat” of the powerband on the 144 because there is no torque to help out.  This forces a lot more clutch action and shifting on the 144 also. The ability to ride the 250F somewhat lazy doesn’t crossover to the 144. Although I believe, the engine makes enough horsepower to race with a 250F it requires much more precision to ride. 

When it came to suspension, there were also differences. Although they use the same forks and rear shock the 144 is sprung softer than the 250F.  Knowing that in advance I thought I would feel the difference more so than I did. The stiffness of the suspension on both bikes felt comparable to me. The 250F definitely had a more planted feel, which may be attributed to the engine just as much as the suspension. As I said earlier, the 250F wants to stand up more than the 144 giving it more stability. This was especially true at higher speeds. The 250F seemed to be less bothered by bumps and roughness than the 144. The 144 skipped around and swapped out more than the 250F but was not something I would consider a major issue. Both bikes seemed to resist bottoming very well. At 185-190 lbs usually my biggest complaint about the Jap bikes is the soft suspension. Not the case with the KTMs. I was very impressed with how well the suspension worked in stock trim for my weight. 

 

Although both bikes are motocross/supercross specific models, here at 2Wheeltimes we know many people purchase these bikes for off-road riding as well with the addition of a spark arrestor. With that said, we decided to give a little feedback for off-road applications. I believe the 250F is a good bike for most off-road riding. I cannot say I think it is a superb bike for any one particular application but with some suspension adjustments, it would be a safe bet for anyone doing a variety of off-road riding. It’s definitely light enough for aggressive single track riding and has just enough power for more open, fire-road style terrain.  On the other hand, the 144 is a great bike for technical riding. If knarly rock sections and nasty goat trails, are your cup of tea than the 144 should get some consideration. I felt the more technical the terrain the more I liked riding it. It was great for technical hill climbs as well. Anything more open and less technical I would rather ride the 250F. It just takes allot more work to go as fast on open terrain when riding the 144. 

Another topic worth mentioning is maintenance. Most people already know that these new generation four-strokes require a bit more maintenance than 2-strokes and more maintenance means more costs. Anyone who rides often or races regularly will appreciate the low maintenance cost of riding a two-stroke. Two-strokes are also less complicated engines, which mean most average Joe’s can still work on them. Not to say the four-strokes have to be taken to a dealership to perform service work, but they are a bit more complicated.

So what does all this mean in the end??? I will answer this question by asking a few questions. If you desire a bike that is easier to ride, in many instances can be rode faster, and in most cases more stable then you will probably prefer a 250F.  It requires less work to ride fast and less precision with throttle position and gear selection than the 144. All the factory pros are riding 250Fs and probably for good reason. Anyone who wants to be the most competitive they can be would probably choose the 250F for race time. So why would anyone want a 144 then??? The bike is just plain fun to ride. If you aren’t trying to win nationals and you don’t necessarily care about shaving tenths of seconds off your lap times then the 144 will put a smile on your face, guaranteed. It feels like you’re riding a mountain bike with a motor, it’s that light. It has the fun-factor that you don’t get on the 250F. On the other hand, I believe anyone who is trying to become a better rider should consider the 144. The bike will make you sharpen your skills and ride with greater precision. As mentioned before, anyone putting serious hours on their bike will appreciate the lower cost of maintenance with the 2-stroke as well. 

There you have it. Those of you that appreciate the 4-stroke, leave the ratio-rite at home and go snag one up off your local dealer. Anyone who still prefers the smell of premix, keep these ring-dingers alive by buying one. Either way, it is all about twisting the throttle on these 2-wheeled bundles of joy. You really can’t go wrong with either choice. Now get out and Ride!!!

Report Card: 2008 KTM 250SXF