First Test: 2006 KTM 250 SX - Dirt Rider Magazine

For the past few years the KTM factory bikes have been some of the trickest looking in the pits. Sure, they show fine on the track, too, but up close they are awesome. For 2006, KTM is selling most of the look and some of the performance of those factory bikes. The unwritten subtext in its '06 literature is this: KTM guys are going to buy the bikes no matter what they look like, so it is aiming at a younger audience with the hot new graphics and jet black frame, rims and outer fork tubes. Another KTM trait is to update all the bikes in the line, and the 250 SX is no exception. Since the introduction of the current engine design in '02, KTM has spent every year toning down its massive rush of power, but for '06, the Austrians turned up the boost, and this is one snappy and muscular top-fueler of a 250 two-stroke.In addition to engine changes, the swingarm, frame geometry and suspension were upgraded, modified or replaced. Clearly KTM hasn't given up on two-strokes.Track TimeWhat a change from last year. The '05 model was Mr. Mellow in power delivery and in the nature of the suspension. It could almost be considered lazy when pitted against the other 250s. Well the '06 has some aggressiveness to it. From the first rip on the throttle, it is apparent the enduro department at KTM was locked out of the porting room. The SX has snap right off the bottom, another step in the midrange and pulls into a healthy top-end. Perhaps it signs off a little harder than some would like, but it is possible the juiced response and mid-hit made the top feel a little lackluster compared to past generations. At least these power observations were true after a little jetting. The good news is the spares kit included the correct jetting for our conditions. We stayed with the stock 158 main jet but exchanged the NIEF needle (position 3, the clip in the middle groove) for a NIEG needle. We kept the clip in position 3. The stock 42 pilot jet was punted in favor of a 40. With the new jets, the engine ran extremely crisply, but unlike past KTM two-strokes, we did occasionally hear some pinging when we loaded the engine hard. The same is true of all the Japanese machines, so two-stroke pilots may want to keep a little race gas or some octane booster on hand.The clutch with its new Brembo master and slave hydraulic units has a longer engagement that makes it easier to feel the exact bite of the clutch plates. Side benefits are a lighter pull at the lever and the ability to fill the unit with common brake fluid rather than the mineral oil the Magura demands. Brake fluid is easier to find and is more heat-stable as well.Transmission ratios are right on. Second is a bit taller (so it is closer to third gear), and it seemed to pull longer than most other 250s, but the motor has the meat to pull it easily. Some riders felt they were shifting too much and thought overrev would have helped.KTM sparked the handling right up, too. The steering headpipe is pulled back 3mm and lowered 5mm, and the rake is a bit less than .5-degree steeper. We felt the steering accuracy and traction was much like that of the KTM 250 SX-F, and it turns out the steering-head changes were to make the frame like the SX-F. With the steering head and suspension upgrrades, KTM found new stickiness for the front tire. It hooks and bites better going into turns whether there is a berm or a rut or not. The slower the turn the more noticeable the added front wheel traction. Stability remains a mix. When the rider is standing, the chassis feels long enough and comfortable at speed with no dancing or busyness from the rear wheel. But there are times when the front end dances a little in the higher-speed rough, but it doesn't escalate into headshake.At first the suspension feels pretty stiff, and with the changes KTM made, it shouldn't be. All of the WP components take some break-in time but grew smoother after Lewis and Tod Sciacqua beat the piss out of it, overjumping everything (Sciacqua) or coming up short (Lewis). KTM changed the shock so that the second (PDS) piston doesn't have as much effect on the low-speed. The valving is refined, and a longer, more progressive bump rubber is used for a better bottoming feel. The outer fork tubes utilize a better friction-reducing coating and have a better internal finish. The inner tubes benefit from a different prep before they are plated to reduce stickiness, and the taper of the steel inner fork tube is changed between the two Teflon bushings. Internally, the fork has a more effective mid-speed valve, and that allowed engineers to increase the low-speed damping in the compression base valve and reduce the high-speed valving.Even so, some riders found the fork harsh, and we eventually traced the problem to rear shock preload. KTM specifies approximately 35mm of bike sag and 110mm of race sag with the rider on board. If the rear end gets too low (too much sag), the fork feels terrible. One rider found that a single turn of shock preload made an enormous difference in plushness and control at both ends. With the KTM it definitely pays off big to attend to your suspension setup.Once you get the setup dialed, the bike soaks up the rough well. It gained the most coming out of turns in chop. It doesn't kick around as much as it did in the past. It seemed to hold itself up higher and have some more stroke to work with while making the front end a little lighter in the process; keeping it out of the bumps, too. The extra bite of the motor might have helped.The front brake is extremely strong, and the initial bite is too much for some riders. The KTM comes with the same size front disc the aftermarket sells as oversize for Japanese bikes. Some riders welcomed the stopping power, but others felt if they accidentally got sloppy with the brake lever, it could bite them. The rear is OK though a little on the strong side. It is a good match for the front if you like gnarly brakes.The 250 SX is a very light-feeling bike everywhere on the track, especially through the bar. A trip to the scale confirmed it is the lightest bike in its class at 216 pounds and the only 250 two-stroke that is appreciably lighter than the 250cc Japanese four-strokes. It is very flickable, maybe too much so for some accustomed to the KX or YZ.Keep an eye on the single muffler end-cap nut. The KTM axle wrench fits it, and if it comes loose, the whole silencer comes apart. Sliding a .007-inch feeler gauge under the fork seals to let a little fork oil weep past will make the fork feel smoother.So let's recap. A fabulous-looking bike with monster motor and a super-slim riding position seeks aggressive rider who loves major snap and turbo brakes. There is no question the 250 SX is a great bike. The question is whether the bike will have the wide-range appeal it needs to top Dirt Rider's 250cc motocross shootout, and we won't have that answer until next month after getting them all together and under the gun.OpinionsThe biggest problem with KTM MX bikes in general is you have to get used to them, and for someone who rides so many bikes all the time, that can be easy and hard. Easy because I'm always changing from bike to bike, thus can easily adapt to get a good feel for a bike. Hard because getting used to the way the KTM does things, so I can really push it, is difficult. The SX is just that much more different that it takes more time than I can give it. Did I say the KTM style of being different was not as good as the other bikes? The answer is no, and in fact some of the traits of the KTM could be better for me if I'd give them time. There is no denying the KTM has a strong and fast motor; this year it is even exciting, with a punch that will stand out even come shootout time. The handling has gotten better every year, and the leaps the PDS suspension has made are impressive. There isn't any reason for not considering the KTM when looking at 250cc MX bikes. Unless you are afraid of getting used to it.Jimmy Lewis5'1o"/175 lb/Vet ProOf all the two-stroke 250s, the KTM is the easiest to make comfortable for my height and riding style. The stock bar has plenty of adjustment and I merely add an Enduro Engineering seat-perhaps even a tall one-and I am good to go for ergos. I can get more than enough power by pouring gas in the tank, and the only hand the brakes need is my right one on the lever. I'm always impressed at how well the KTM holds up. It just keeps looking and feeling new. I like the KTM 450 better, but the 250 SX is just fine.Karel Kramer6'1"/2O5 lb/NoviceKTM 250 SXWhat's New* Cast swingarm is 20 percent stiffer for better stability.* Fork has friction-reducing bushings and coating, plus more progressive settings.* PDS shock has new internals and settings as well as a new bump rubber.* Frame with a lower, pulled back and slightly steeper steering-head angle for more precise cornering.* Rear master cylinder has a new shape to holes inside the master cylinder and new seal material to increase reliability.* A Competition kit with plastics, stickers and spare parts comes with the bike.* Engine changes include the power-valve flap, timing and governor spring in conjunction with modified porting.* Lighter piston.* 2mm-smaller carburetor, the PWK36AG instead of the PWK38, for better throttle response without losing top-end power.* Gearbox with a taller second gear that is closer to third gear.* CDI with 16-bit processor and new ignition curve.* Brembo hydraulic clutch unit with a softer pull, longer engagement point and designed to use brake fluid instead of mineral oil.What's Hot* Bike has a look that most everyone loved.* Power is strong with a solid hit in the midrange.* Brakes are extremely powerful.* Lightest bike in the class.* Handlebar mounting position (four-way) and fork offset (two-way) are adjustable.* Brembo hydraulic clutch setup improves feel and lightens the pull required.* Steering is more crisp and accurate.What's Not* Some riders found the hit a little violent.* Black rims require care when changing tires to avoid scratches.* Fork guards can mar the black finish on the outer fork tubes.SpecificationsMSRP: $6298Claimed weight: 208 lbActual weight (ready to ride, no gas): 216 lbSeat height: 37.2 in.Fuel capacity: 2.0 gal.Aggressive OrangeRiding Impression: 2006 KTM 125 SXIn 2005, the KTM 125 SX was praised for having the best engine in the class along with having great standard equipment and strong brakes. This year, KTM made several changes to the 125, including a Grand Prix-style cylinder, an improved exhaust pipe and a V-Force reed valve. The appearance of the bike was also modified via new black frame, fork tubes, anodized black rims and edgier-looking graphics.On the track, the 125 SX was a bit difficult to dial in. The stock jetting-which must be for break-in only-was quickly forsaken for a different setup, as power consistently fell off and cut out. We ended up changing the needle from a 1469D to a 1469G while staying on the second position and then swapping out the 188 main jet for a 190, but we left the pilot jet at the stock 45. This revised setup-the same jetting we ran in our 2005 125-allowed the bike to rev higher and produced much smoother power, the most usable of which is found at high rpm; the rest of the spread is lackluster at best. The KTM puts out a solid amount of ponies up top, and if you keep it in the meat of the power, the bike is a rocket. Definitely more aggressive than last year.The new six-speed transmission feels fairly smooth on the SX, thanks to decent spacing and a solid feel. Some of our testers felt the bike popped into neutral too easily, but other than the clutch pull being slightly heavier than we would have liked, we had no complaints.Many KTM 250 SX chassis changes appear on the 125, aiming to give baby brother a more aggressive yet planted feel. For the most part, the 125 rode well on outdoor tracks, though the shock's high-speed compression was weak in rougher sections. We had a hard time getting the linkageless shock to cooperate, but after boosting the high- and low-speed compression settings and going out three clicks on the rear rebound, we arrived at a satisfactory setup. The front wheel seems more planted than it has in the past but lacks the weighted feel some of the other orange models offer. There wasn't too much push or drift when turning; the front wheel just has a way of hopping out of ruts.The brakes on the KTM are incredibly strong and are very touchy for at least the first few laps, until the proper amount of corner braking is figured out. Ergonomically, the SX is definitely different from a Japanese bike but has a great feel once you become used to it. The standard oversize bar is awesome, and the pegs and bar relationship put the rider in a good neutral, over-the-bike riding position. Compared with any other 125, the footpegs feel slightly high, but the bike is also slim and flickable.Overall, the KTM 125 SX is an aggressive bike that likes to be ridden with an even more aggressive style. It looks tough, it handles fairly well, and the top-end power is amazing. With a bit more work to the jetting and suspension this bike could be a threat in the 125 two-stroke class, though a bit of a long shot. Find out how it ranks in our upcoming 125 shootout, which will be featured in both Dirt Rider and Mini Rider magazines.