KTM Dirt Bikes: 2012, 2011, and 2010 Models.

The new 2011 KTM 450 SX-F is the least changed in the KTM dirt bikes motocross lineup. Consider that's taking into account an entirely new frame, rear suspension system and airbox/bodywork and the scale of KTM's 2011 new models really comes into focus. It's no doubt the 2010 450 SX-F was the best KTM 450 MX bike ever. Its power was close to perfect and the suspension and chassis found the magic spot of plush and controlled with insane cornering. For 2011 this seems to continue.

The 2011 450 SX-F remains firmly planted on the ground with great front and rear traction and easily one of the most enjoyable power deliveries in MX. The 2011 powerplant retains all of 2010's pleasantries with more refined carburetion and spot-on delivery. It comes on so strong and smooth it's almost magic. There is plenty of ferociousness in the mid if you want to snap the throttle to that range but why would you when you can drag the bike through lower rpm with beaucoup surge. All of this power and control only helps the bike corner in control.

For some, the carburetor on the 450 will come as a surprise. As every other 450 MX bike is now fuel injected, it seems out of place that KTM dirt bikes will stick to jets. According to KTM, there were a few main reasons to stick with the carb. One big one was cost. The addition of EFI on this bike will bump up the price. Another is weight. KTM hates adding weight to bikes unless it's worth it in improved performance. Lastly is performance. Apparently, every tester in KTM's camp preferred the power delivery of the carbureted bike. Guess what that means: the 450 SX-F has a carburetor for 2011 but there is at least one in the testing fleet that has EFI so the transition can't be too far off. We'd guess the 450 will get a major motor update soon with EFI included.

The linkage shock system on the 450 seems to only help the calmness of the ride and should make track-to-track changes less drastic. KTM's have always been highly sensitive to ride-height, fork height, etc. The linkage may give them more middle ground for a range of settings to work across different tracks.

Compared to the 2011 KTM 350 the KTM 450 easily dominates in the lug-and-chug category as it does in outright power. Where the 350 SX-F can dip into low rpm around turns and still recover quickly, the 450 can rocket away at any time below even 7,000 rpm. The 350's edge seems to be on top where it not only pulls just as hard but also feels lighter, more planted and seems to get better traction.

2011 KTM 350 SX-F:

In 2006, Stefan Everts was reigning world champion (with a mere 14 victories in 15 Grand Prix) and then he became KTM Race Director. Back then, he could already see where the future of motocross was heading and in KTM USA and KTM Europe he found an ideal partner for his vision: efficient and maximum practicable performance from smaller displacements in an overall package that's tailored unconditionally to the requirements of the rider. 4 years or so later, it's ready: the new 350 SX-F KTM Dirt Bikes. With a new engine, fuel injection system and smaller displacement, new bodywork, new chassis - in fact, a whole new concept. What with the first Grand Prix victory and racing to the top of the overall standings in the MX1 class after only two races, maybe even the beginning of a new era in motocross

2011 KTM 250 SX:

For years the 250 SX KTM Dirt Bikes have been delivering plenty of 250 two-stroke punch with a handful of torque to keep it under control. You can grip and rip or tug and lug—the choice is yours. It’s been a really good bike for spoiled four-stroke riders to get their manly-bike fix on and with the immense improvements in handling and suspension it’s becoming a cult favorite for die-hard two-stroke motocross racers. Free riders and FMX junkies dig it because it is light, powerful and durable and it makes a pretty damn good off-road bike with some simple mods as well. It’s basically easy to love.

The 2011 KTM 250 SX has continued the development of this workhorse with new cylinder port locations, timing and exhaust valve enhancements. The power picks up with a bit more snap than previous 250 SX KTM Dirt Bikes though KTM called it response, not snap. It is still one of the gruntiest and smooth two-strokes you’ll ever ride yet has wrist to rear wheel control that is nearing perfect. If you want to argue about how fast the bike is then you need to see a mental health professional as these KTM Dirt Bikes move. Sure you hit the wide-open part of the throttle more than on a 450cc four-stroke but you don’t hold it there forever like on a 125 or 150. The overrev on the 250 SX is clean and long and you won’t bend any valves here.

The suspension has taken a step forward. Gone is the wallowly feel in the rear, though it has gotten better and better each year of the PDS system, but it seems the new arrangement is allowing some added stiffness without the downsides of rider comfort. The bike rides a little higher in the back and therefore turns even easier than before, with no hint of added instability, a common tradeoff. Light, flickable, easy to change lines mid-turn, and easy to move around on, the bike is really good and more fun than ever.

Everyone is asking why the KTM 150 SX and the KTM 250 SX didn’t get the linkage rear shock and the answers we can give are pretty simple. First is weight. Linkage systems add weight and KTM isn’t the kind of company that adds weight without having undeniable benefits attached. Second is cost, the entry-level two-stroke range is one KTM has a handle on. We doubt KTM Europe and KTM USA would risk pricing themselves out of the market with a feature they don’t feel they need. Third is use. KTM knows people aren’t using these bikes at Supercross races and in doing so they feel the PDS linkage-less system is just as good everywhere but the unique demands of the Supercross track. Everything in the world of motorcycle production is a compromise and KTM obviously doesn’t feel the addition of a linkage to the two-stroke lineup is beneficial. If they did, they’d bolt it on. They already have the frames and swingarms lying around.

2010 KTM 450 SXF:

For 2010 KTM Dirt Bikes made some big improvements, which should make the other moto manufacturers nervous.

For 2010 KTM USA engineers focused on two areas of improvement for their successful KTM 450 SXF Model: Versatility and Handling.

Versatility comes with the addition of a new five-speed gearbox for the KTM 450 SXF. Based off the popular transmission in the XC line of KTM off-road dirt bikes, the SXF gears are shortened up a bit for motocross. The KTM Dirt Bike engineers also designed a new titanium exhaust called HPRS (Head Pipe Resonator System) which incorporates a "Noise Resonance" chamber on the header. This is the first inclusion of factory race-team exhaust technology into production moto bikes. KTM talk reveals the primary purpose is to reduce sound while not affecting power.

Other motor updates include a leak-jet equipped carburetor for 2010 (with jetting updates to match) and a piston with a .5mm thicker crown (to the underside). There's also a coating on the big-end crank bearing to help with longevity.

Why no fuel injection? Well....KTM talk reveals slapping EFI on their moto bikes without significant performance improvements is not their style. They'd rather build a bike around a major change (like when they added the electric start) instead of the other way around. Also, they're not about to bolt on the extra weight of the EFI kit just yet. KTM has had good success with their carb and are sticking with it...for 2010, at least.

Handling changes outnumber the motor updates for 2010 on the KTM 450 SXF. New triple clamps are now fixed at 22mm offset. Those clamps are also re-designed to keep the clamp area around the upper fork tubes from ovaling during use. KTM USA hopes to eliminate some of the "twitchiness" on the front end some moto racers experienced at high speeds on earlier models. They want a more stable, less affected by impacts, chassis feel as well. That's why KTM engineers dropped the frame on the head-tube 10mm. This change, combined with a 4mm shortened shock gets the whole KTM chassis closer to the wheels and lowers the center of gravity. Also the backbone from the shock tower to the head tube becomes less straight and more curved. The improved flex characteristics are to absorb more rear shock impacts and keep the bike going straighter, longer.

The fork receives a re-valve with stiffer settings and some low-friction/reduced stiction seals and bushings.

KTM has a history of amazing brakes. And for 2010 KTM upped the bar with the SXS Factory-Style Brembo front caliper.

Some of the first things moto racers are noticing is improved turning characteristics compared to last years model. Some riders complained the 2009 model had some front wheel tucking on flat track turns as well as the front-end feeling busy at speed. However initial feedback on the 2010 450 KTM Dirt Bikes reveals a lot more stability and really good traction control, as well as improved feedback in both the front/rear end. The other thing moto racers are raving about is the new five-speed transmission. The motors on 450 KTM Dirt Bikes have always been strong and easy to ride, however the 4-speed transmission hindered the bike on certain tracks. With the incorporation of the new five speed for 2010, KTM dirt bike engineers have focused on making the power much easier to control and more versatile.





2011 KTM 250 SXF:

Time has proven you can always find massive power on tap with the 250 SX-F KTM Dirt Bikes. But designers at KTM USA & KTM Europe wanted to fill in the bottom end and mid power for 2011 as they built in the ultra-responsiveness of the EFI system. The power combination seems to be working with a more peppy punch coming from the 250F. The power still holds its top-of-the-line controllability and fun top-end pull but thanks to EFI, the responsiveness is now a form of brainless fun.

The new chassis shared across the SX-F line is nice on the 250F. These KTM dirt bikes feel a little lighter while still staying planted and the new linkage-equipped shock seems to be settling in nicely. The bike corners like a dream. It settles quickly and keeps its attitude in check through the turns.

Compared to the 2011 KTM 350 SX-F the 2011 KTM 250 SX-F feels much softer on bottom and across the rpm spread. The bike responds more to clutching than the 350 SX-F and wakes up when given a flick of the lever. Plus, the bike still revs out great. It screams where the 350 roars, no doubt a 250-class top-end leader, for sure.

2011 KTM 150 SX:

The KTM 150 SX is the smallest-bore motocross bike to share in the trickle-down technology the 2011 KTM 350 SX-F development project brought to KTM Dirt Bikes MX lineup. Starting with this bike we see the same new-generation KTM frame styling and geometry (with revised shock “tower” mounting). This allows the PDS shock to grow longer and lay down more. The shock is still offset to the right side of the bike a bit. It isolates the shock forces away from the main frame spars too.

Performance improvements are concentrated on refining and optimizing airflow into the engine. Along with new styling benefits, the new airbox/rear fender/side panel business is hiding a specific airbox intake tract for the 150 that is supposed to get the oxygen to the lungs right on time.

The 2011 KTM 150 SX dirt bikes look awesome, and they sound pretty sweet, too. Even though the spring rates may be soft for 180-195 lb dudes, these KTM dirt bikes still handles surprisingly well. Stiffening up the fork to keep it from diving and slowing down the rebound will keep heavy riders happiest. The motor sings, like it should, and after feeling the sweet pick-up in the mid range, it can make the smallest bore four-stroke sure feel sluggish in comparison. This bike is insanely fun to ride and is the only small-bore two-stroke with this level of quality components stock. Insane brakes, hydraulic clutch and a VForce reed cage are topping the list of trick must-haves for the motocross elite in this class. With the 2011 KTM 150 SX you get good torque for a small-bore, incredible mid-range punch and a good over-rev that is working right. This isn’t a tuning intensive built-at-home big bore kit. Those modified bikes can be tough and often provide little success. Taken from the original 144SX KTM Dirt Bikes of the past, this bike is working immensely better.

2011 KTM 125 SX:

2011 KTM SX 85 :

2011 KTM 65 SX :

2010 250SXF KTM Dirt Bikes:

For 2010 KTM Dirt Bike engineers made following improvements to their already successful KTM 250 SXF model:

- New 22mm offset triple clamps. This new clamp uses only two bolts on the lower portion and is designed for more flex compared to last years models for improved feedback.- New low-stiction fork seals and bushings for improved suspension performance.- Modified air box design with molded-in lip to keep water from splashing onto the air filter.- Twin Air Filters are now standard.- Toyo B153 brake pads now standard to provide a more progressive feel.- Renthal handlebar grips are now standard.

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