KTM is one of the only manufacturers still making a 125cc 2-stroke and actually making upgrades to it.
KTM rocked the motocross boat last year when they brought out the electric-start only, 450SX-F. Nothing so radical highlights the release of its 2008 motocross bikes, but the Austrian manufacturer has made updates to most of the high-profile MXers in the lineup.
Unlike some OEMs, KTM has yet to abandon the 2-stroke and not only brings the 125 and 250 SX to American shores, but the 144 as well. This hardly means they’ve neglected the Thumpers as a trio of 4-strokes is headed across the pond as well in the form of a 250, 450 and 505SX-F models. All of the full-size motocross bikes have a shared list of improvements, including: new graphics, Renthal 996, strengthened front fender, wrap-around fork guards and suspension upgrades.
Fine tuning the WP fork required keeping oil in and grit out with more efficiency. Low-friction fork seals and improved bushing seals in the outer tubes help the fork slide smoothly through its stroke. Updated valving give the bikes better bottoming resistance and the bottoming stop is reshaped for a better reaction when the suspenders are taxed. Every SX and SX-F model gets the same aluminum shock body from the ’07 450SX-F. Again the bottoming resistance was targeted with internal valving as well as stiffer spring rates for all motocrossers except the 125SX and 144SX. The transfer holes from the body to the reservoir have been reshaped for claimed high-speed damping improvements.
For specific model changes, the 125 and 250 are the only 2-strokes that get any special attention. The 125 has a remodeled piston, modified engine cases and a new ignition curve. The 250SX also gets the revised engine cases which reduce the volume of the case-reed induction which leads to increased velocity and improved throttle response. A lighter connecting rod is also installed in the quarter-liter.
Katoom’s Lites-class 4-stroke is mostly unchanged. The 250SX-F gets a new exhaust cam shaft, valve springs and silencer. It also has a larger-diameter steel head pipe and revised ignition curves aimed at low-rpm performance. Unlike its bigger brothers, the 250SX-F is still kick-start only.
The electric-start 450SX-F is still the marquee machine for KTM. The big-bore thumper gets some minor massaging for 2008, but nothing like the e-start bombshell from last year.
As for the big-bore models, the 505 is unchanged except for the universal upgrades, but the 450 has gotten a gentle massage. Some of the changes are aimed at shaving weight from the motor with a lighter crankshaft and counterbalance. On the other end of the hydraulic clutch, the clutch shaft and inner hubs are revised for better oil flow. It has a new exhaust cam and timing to go with the updated muffler.
All of the bikes have the same general look to them that really caught our eye last year. The black fork tubes, steel-tubular frame, Excel rims, fuel tank, seat and muffler add to the mean-and-nasty physique. The one-piece side panels/rear fender still offers minimal decal space and expose practically the entire silencer. Specs and MSRP figures are not yet available, but the small amount of tweaking rather than major overhauls should keep costs close to the 2007 figures.
As for the smaller machines, KTM is offering six options for the youngsters. The 50 Mini Adventure, 50 SX Jr. and 50 SX all received graphic changes for 2008, as did the 65, 85 and 105 SX. The 85 SX joins the three smallest as a carryover, but the 65 and 105 have noteworthy changes.
Both machines get brake discs that are made of softer material. KTM claims these new rotors keep the temperature lower and increase the life span of the brakes. The 105 also has new pads and a smaller rear brake master cylinder. The rear shock has new settings and the damping spindle on the front fork shrank from 14mm to 12mm.
Let us know what you think about the 2008 KTMs in the MotoUSA Forum.