Test Ride: 2004 KTM 105 SX

The 105 SX features top-shelf... 

   

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The 105 SX features top-shelf equipment, keeping it looking and feeling new throughout our test.

KTM has shed any perception that it is a "small" company. It's been less than a decade since the Austrian manufacturer actually was a small one, but it exploited niche models with unusual, though desirable, engine displacements. Basically, it built what it felt serious off-road and motocross riders wanted. In a unique move for a European company, KTM began doing suspension and preproduction testing in the United States to ensure American riders got suspension that worked for them. It also paid attention to the off-road rider, and it made sure each dealer had a wide range of models suited for off-road. Then it rebadged some Italian 50s as KTMs, thus entering the minibike scene. The beauty of the modern KTM brand is that the company saw the potential in the market after the initial sale of machines, so it insisted that any motorcycle with its name on it be a quality product. Rapid advances in the 50 market were followed by the production of an ultracompetitive 65. Naturally, a competitive high-performance 85 SX race machine ensued. In addition to having the best engine performance in the class, the 85 SX seems to be gaining the same reputation the larger KTM two-strokes have for longevity. The final gap in the KTM model lineup was a 105cc-class (sometimes called big-wheel or Supermini) racer. These models are generally raced only at large amateur events, but they fill a larger and perhaps more important role as off-road options for riders too tall for 85cc machines but too short or light for 125, 200 or small-bore four-strokes.

Even in I-5MX's sandy loam,... 

   

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Even in I-5MX's sandy loam, Sean Friday had no trouble getting the bike to pull out of berms in a hurry.

Honda, Kawasaki and Suzuki all make machines for the Supermini class. Basically, the bikes are 85s with 16/19-inch wheel combos in place of the 14/17-inch wheels legal in the 85cc class. In fact, until the KTM's arrival, only Kawasaki made a big-wheel machine (sold also as a Suzuki model) that is actually 100cc. Suzuki also sells a big-wheel version of its RM85 (the RM85L).

KTM chose the same route when building its 105 SX. It has the larger wheelset, and like Kawasaki's KX100, it gained displacement via a bigger cylinder bore. As is true of its 85cc sibling, the 105 boasts an exceptionally robust frame and suspension. It has a larger, fully adjustable shock than other bikes in the class, as well as a 43mm inverted fork whereas its classmates use a 35mm! The KTM is also the largest bike in the class physically and has the most-open and -roomy riding position. Like the full-size KTMs, the 85/105 has a top triple clamp with a variable handlebar location (count them: You get four choices) to fine-tune the riding position.

We compared the 105 SX with the 85 SX on the track. The larger cylinder bore gives the engine an entirely different feel from the smaller motor. The 85 has excellent torque and roll-on response for an 85, but the 105 has much more torque in the lower rpm ranges—so much so that the engine almost feels like an enduro motor. It doesn't even seem to make as much high-rpm power as the 85! That opinion could be wrong; the engine pulls so strongly down low that the top-end rush isn't as noticeable. We had no complaints that the 105 SX was slow. Instead, we simply heard how effortless the bike was to keep in the power. Any rider light enough for a mini will barely need the clutch in turns. Jumps right out of turns are also pretty effortless.

As with the 85 SX, the 105's suspension could have used a little more tuning than we were able to do with clickers. The front-to-rear balance is off. Our less-than-110-pound testers couldn't get the sag to measure correctly. The rear spring is stiff for lighter riders, and the fork is soft for heavier pilots. Most of our riders were still pretty happy with the handling and the action.

The 105 SX chassis is very... 

   

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The 105 SX chassis is very cooperative, but the torquey engine makes roosing like this possible.

As we did with the Japanese 2003 big-wheel models (June '03), we installed a spark arrestor and took the bike out on the trails. For the trail testing, we corralled women and riders too tall for an 85 yet too small for a 125. All loved the 105 off-road. The smooth power is outstanding for trails. The chassis' longish, stable feel gave riders confidence in deep whoops. Turns onto sharp climbs are always the weak point of small-bore two-strokes, but the KTM makes those as easy as with any small performance two-stroke we've tried.

Like the 85 SX, the 105 is a solid-feeling moto and off-road machine with good ergonomics. The engine performance is very strong yet docile enough for less-experienced riders. Compared with other bikes in the class, there is more engine vibration, but it didn't bother our crew. Also, the rear brake lacks feel and is somewhat sensitive, and the pads wear fairly quickly. Otherwise, we wouldn't hesitate to buy one for moto or for any type of off-road riding where it is legal.

Opinions

At 5 feet 3 inches, I've found that the number of bikes that fit me is fairly small, and the trails I ride are too aggressive and rough for any of the beginner models. A big-wheel minicycle is about as large a bike as I feel confident riding. I normally ride a Honda CR80R Expert (big-wheel), but I fell in love with the KTM 105 SX. It's the best bike I have ever ridden. It has all the power that my Honda has and more, yet the power-valve engine has a lot more torque at low rpm. The power comes on smoothly, is easy to control and transitions to the pipe less suddenly. I like the riding position and the planted feel the chassis gets from the large-tube frame and beefy fork. The suspension was fine over sharp, choppy bumps, but it really shone in deep whoops. On the other hand, I did have a little more trouble touching the ground than I do on my Honda. Still, if I could get a green sticker for it (my Honda got one under the 1997-and-earlier grandfather clause), I'd buy the KTM in a second! If I could afford two bikes, I'd still get a KTM and just ride it during the times of the year when a red-sticker (closed-course) bike is allowed.
Wendy Jo Carswell/5'3"/120 lb/ Expert trail rider

I have a lot of time on the Kawasaki KX100 and the KTM 85 SX. I like the bigger wheels of the 105; they make the bike feel more stable at speed, over jumps and through whoops. Plus, the rear brake doesn't seem as prone to lockup as the 85's. I appreciated the fact that the 85 and the 105 stayed looking and feeling new after they were ridden, and I even like the stock aluminum handlebar and the grips. The engine pulls hard all the way through the rpm range. At the I-5MX and Piru Motocross Park tracks, the 105 was especially potent on the hills, and even though its power is smooth, it feels faster than the Kawasaki KX100. The number plates are a pain to put backgrounds and numbers on, and the bike pulled so hard it tired me out a little more quickly than an 85 SX would. But the 105 is still a winner.
Sean Friday/5'4"/118 lb/Novice motocrosser