2005 KTM125 & 250SX

In the early 1990s KTM became very aggressive in the motocross market, especially in professional racing circles. With top riders winning World Championships and dominating in Europe, KTM soon set their sights on the U.S. National and Supercross circuit to hunt down similar success stories and prove their equipment in the most competitive series of all.

In 2001, orange rider Grant Langston took the 125cc National Championship battle down to the final moto in Steel City, only to lose the prestigious title at the end of the day to Mike Brown, the result of a broken rear wheel and a killer case of bad luck. Still, both Grant and KTM got their revenge last year by going one-two in the very competitive 125cc Nationals, with Langston winning the championship and Ryan Hughes finishing a close second. The outdoor title marked KTM’s first in the States and gave the Austrian company some well-deserved respect.

Erase Bubba Stewart from the mix and the KTM125SX is the only two-stroke to consistently be competitive in the 125cc Nationals this year. In the World Championship scene at press time, KTM was leading the points series, with Ben Townley at the helm of a works 125SX and Tyla Ratray hanging on to a close second, also aboard a KTM125. That is a pretty big accomplishment when you consider the enormous horsepower of the oh-so-popular four-stroke 250cc machines. In a motocross world that seems to be completely dominated by four-strokes in this day and age, KTM is one company that is keeping their two-stroke guns-a-blazin’. For 2005, the two-stroke tigers have both received major updates with new frames, trick, adjustable triple clamps, and plenty of other new hardware that promises to keep both bikes competitive in a market that seems headed for thumper supremacy.

FASTER THAN EVER

For as long as we can remember, KTM hasn’t had much of a problem in the horsepower department. Both the 125 and 250cc machines have enjoyed rocketship power plants that year after year our test riders rave about, and 2005 is definitely no different. The 250SX is possibly the fastest production 250cc two-stroke we have ridden to date. It’s a bit sluggish off the bottom, but it hits hard in the mid and pulls, well, pretty much forever!

The top-end power and over-rev areas are where this motor really shines, but let us assure you that there is plenty of power to be had throughout. We did make a few jetting changes to clean up some slight bottom-end hesitation felt by our faster test riders, and once we got the initial hit in the ballpark we discovered our only real complaint. Some of our test riders still felt that the motor could benefit from crisper roll-on power; however, we’re sure that with more jetting changes and tinkering, finding the right setup is possible.

A bigger crankshaft diameter, dual piston rings, an all-new cylinder design and modifications to the carburetor make up the extent of the motor changes, and they all work harmoniously to create a power delivery that is extremely rider-friendly without compromising any horsepower. To sum it all up, KTM did exactly what they attempted to do. The motor will not only be raved about by top pros for its absolute brawn, but less-talented riders will also be stoked with the manageable power.

The 125SX didn’t receive quite as many motor changes, but if you are at all familiar with the typical engine characteristics of the 125SX, you already know it didn’t need much to remain competitive, even against its more powerful thumper competition.

In a nutshell, the KTM125SX motor flat out rips! Like its big brother the 250SX, the 125 is a bit sluggish or soft off the very bottom, but when it hits the mid range, you had better be holding on tight! The smack of mid-range power is followed by a stunning top-end and unmatched over-rev that is truly incredible. Experienced 125cc riders will have a field day with this motor. It is built to ride at high rpm, and it’s definitely made to be ridden aggssively. A flick of the clutch out of a turn mixed with full throttle acceleration will leave even the pickiest rider grinning. It’s not so difficult to see why this bike is leading the world, blessed with a motor like this.

SUSPENSION UPDATES

KTM has taken some heat over their linkless suspension for some time now, but they believe in the system and continue to improve it every year. Advantages to a linkless setup are ease of maintenance, loss of overall weight, and the ability to work with a straight shock ratio instead of including all of the variables of a link. The disadvantage is trying to set a shock up to work in all conditions without the help of a link ratio. Not an easy chore.

For ’05, KTM has updated the shock body and modified the piston rod for improved damping characteristics and bottoming resistance. In the past we complained about a lack of traction on acceleration bumps and the harsh feel transmitted through square-edge hits. The shock updates have helped both cases tremendously. Traction was noticeably improved and the big hits went without comment.

The forks on the KTM are as trick as production forks get. The WP units have once again been beefed up this year, and the inner and outer fork tubes have been balanced to keep the forks flexing equally in all that nasty chop. Before, the forks had a tendency to flex, causing the bushings and seals to bind and in turn transmitting some seriously harsh hits on deceleration situations. The new legs with chrome-plated pistons help create less friction, keeping the forks working smoothly.

On the track, both bikes seemed very similar. We had to stiffen the fork setting up quite a bit to defend against some deceleration dive action, but that was the only real complaint. Once we had the compression in the ballpark, we could hammer the bikes without any of the white-knuckle action that we experienced with last year’s setup. Both bikes worked well on the small chop as well as on the big hits.

CLASSY CHASSIS

The biggest change KTM made for ’05 is the frame tubes. Last year both the 125 and 250SX were so fast that the chassis couldn’t keep up with the motors, making the bikes very scary to ride in certain situations. Much of this problem was the flex of the frame, so this year KTM ditched the old school round tubing they’ve been using since the beginning of time and replaced it with an oval chromoly-steel tubing. The new-generation frame has also been reinforced with countless gussets and welds, making it much tougher and less prone to flexing.

The lateral, tubular design is meant to help front and rear end stability, a big problem on the KTMs of the past. Because the shock is mounted on the side of the frame and not directly in the center of the chassis, the KTM previously had a tendency to swap sideways in the whoops or in very rough situations due to frame flex. (If you ever watched Langston in the whoops at an SX you know what we mean.) This new frame design was developed to combat that problem head-on.

Another really cool feature that KTM put into production this year is the addition of a changeable offset, billet triple clamp. This trick-looking clamp can be changed from 18mm to 20mm offset depending on your preference. The 18mm offset puts a bit more weight over the front of the bike, while the 20mm offset pulls the girth back a bit, making for a lighter feel. Both bikes come stock with 20mm offsets, though we switched the 250SX to 18mm, which our pro tester preferred. We left the 125SX alone at 20mm.

On the track, both machines handled noticeably better than last year’s models. Although that isn’t exactly saying that much, we will say that we felt very comfortable in sections that had us holding on for dear life last year. Both bikes tracked much straighter in whoop sections, and the deceleration headshake was at a minimum. The turning prowess of the KTMs was good and the overall character of the entire bike was non-threatening.

IN A WORD; IMPROVED

On the surface, the new Katooms don’t look tremendously different, but don’t let the looks fool you. The frame changes alone are huge! Also, one of our favorite additions is the front fender brace that now comes stock; no more annoying fender slap! The ’04 models had everyone on our staff complaining about the ugly noise heard every time the bikes hit a big bump. It used to sound like the front end was breaking off, but we’re happy to say that the new fender brace cures the problem.

Last year we did our testing on the two-stroke KTMs, and to be honest, returned them to the factory, as they were a little scary to ride. This year will be a whole new story. The updated chassis mods allow the bikes to be ridden to their full potential, and the motors are incredible. It still amazes us that companies are putting so much effort into updating their two-strokes, but at the same time we are stoked to see it. These new KTMs are proof that two-strokes are far from dead.

N A WORD; IMPROVED

On the surface, the new Katooms don’t look tremendously different, but don’t let the looks fool you. The frame changes alone are huge! Also, one of our favorite additions is the front fender brace that now comes stock; no more annoying fender slap! The ’04 models had everyone on our staff complaining about the ugly noise heard every time the bikes hit a big bump. It used to sound like the front end was breaking off, but we’re happy to say that the new fender brace cures the problem.

Last year we did our testing on the two-stroke KTMs, and to be honest, returned them to the factory, as they were a little scary to ride. This year will be a whole new story. The updated chassis mods allow the bikes to be ridden to their full potential, and the motors are incredible. It still amazes us that companies are putting so much effort into updating their two-strokes, but at the same time we are stoked to see it. These new KTMs are proof that two-strokes are far from dead.