First Look: 2017 KTM 125 & 150 XC-W
In MY 2017 the 125 EXC is replaced by the new 125 XC-W. It features all the latest chassis and engine technology of the larger EXC models, but without any homologation features or power restrictions. The 200 EXC is replaced by a 150 XC-W, which provides basically the same agility as a 125, but with significantly more torque and power.
Coming without a COC, these bikes avoid the hassle of ever more challenging homologation rules in the face of a clear trend away from classical enduro races and toward closes-circuit racing for which no registration is required.
Their “XC” stands for “cross country”, while the “W” signifies a wide ratio enduro gear box. Otherwise, these bikes are based on the EXC models, retaining the same type of chassis hardware as well as the latest engine technology.
Being very similar to the European EXC models, their main difference is that they are not street-legal as they do not comply with current homologation rules from the outset, and as such, have no power restrictions. This means that, except for front and tail lights, they are not fitted with any street homologation features. In short: the XC-Ws are defined for closed-course competition use only.
The 125cc 2-stroke powerhouse has been developed using the latest KTM engineering know-how and the most advanced technology available. The results: rugged power and burly amounts of torque across a wide power band, in an extremely compact package that is 2kg lighter than previous models.
For the latest engine generation the KTM R&D team designed lightweight die-cast engine cases featuring a high crankshaft and clutch shaft position, located close to the centre of gravity, which results in a tight mass centralisation for outstanding rideability. In addition, the engine body is extremely lightweight and compact, while still able to house an optional electric starter. The newly designed engine covers also feature an advanced, highly durable new surface structure in order to reduce the wear caused by the riders boots.
The compact cylinder with a 54 mm bore features a cutting-edge power valve unit with a sophisticated mechanism for the lateral support exhaust ports, matched to a twin-component cylinder head. The layout of the water jackets in the cylinder and head guarantees an efficient heat dissipation at all times.
A 150 cm3 cylinder, head and piston unit can now also be fitted to the same engine base, converting the bike to a 150 without replacing the crankshaft. New lateral brackets form a more efficient engine mount via two new head stays.
A wide-ratio 6-speed enduro transmission was designed with its gear ratios specially matched to the 125’s power delivery. The latest production technologies allow for compact dimensions and minimal weight. Keeping safety in mind, an advanced ́No Dirt ́ gear lever design prevents dirt from blocking the joint.
The new KTM XC-W models come as standard with kick starters, while the 150 XC-W also features an additional electric starter. For the 125 XC-W an optional PowerParts kit including all the necessary hardware allows customers to easily retrofit an electric starter should they so wish.
A new 38mm flat slide Mikuni TMX carburettors replaces the previously used Keihin units. They are less sensitive to changes in air pressure and temperature, saving on set-up and maintenance time.
The high-tech, lightweight chrome-moly steel frame is the base of the EXC series’ handling, rideability, precise cornering and excellent stability. Due to wider but lower profiles for the steering triangle combined with hydro-formed side tubes, the torsional rigidity was raised by 20% providing more cornering and track stability.
At the same time the longitudinal stiffness could be reduced by 30%, which results in better absorption of the impact energy from the suspension, in short: more comfort and less rider fatigue. Laterally attached, lightweight engine head stays contribute to a reduced vibration level. Two threaded inserts in the lower cradle tubes make a rugged mount for an optional skid plate. In MY 2017, the EXC frame is 300g lighter than the predecessor and a full kilogram lighter than that of the lightest competitor.
The brand new subframe, manufactured from a new type of strong aluminium sections, tips the scales at less than 900g – 20% weight savings over the previous generation.
An updated swingarm design allows for an optimised mounting position of the PDS (progressive damping system) rear shock for increased progression. Furthermore, the new cast aluminium
MY 2017 design achieves another weight reduction of 220g, combined with perfect flex behaviour.
WP Split Forks
The all-new WP XPlor 48 upside-down fork is a split fork developed by WP in close collaboration with KTM. While it has springs on both sides, the damping action is split between the fork legs: compression on the left side, rebound on the right. The forks are easily adjusted for compression and rebound by twisting the individual dials on top of the fork tubes (30 clicks each). In addition, a longer and sealed hydro-stop guarantees better resistance against bottoming-out.
Due to high-quality materials and a state-of-the-art production process, the new XPlor 48 forks with some 300 mm of travel combine outstanding response and damping characteristics with weight savings of around 200g over the previous generation of forks. In addition, a new, optional preload adjuster allows to quickly dial up one of three different spring preload settings without any tools.
New PDS Shock
The newly developed WP XPlor rear shock retains the signature KTM PDS design where the shock absorber is directly connected to the upper side of the swingarm without a linkage system.
This set-up has now been re-designed with the new frame and swingarm architecture in mind. It boasts the best possible mounting geometry, provides even more progressive damping, and features an all-new shock absorber body with a smaller piston and a larger reservoir.
KTM has reduced the piston diameter from 50 to 46 mm, with the total length reduced by 2.5 mm and the shock stroke by 4 mm, for total weight savings of more than 600g. In addition, it is now mounted 5 mm closer to the centre line, resulting in nearly symmetrical loads on swingarm and frame, as well as more space for the exhaust.
A second piston works together with a closed cup - instead of a needle - towards the end of the stroke and is supported by a progressive shock spring for enhanced protection against bottoming-out.
New Rear Brake Caliper
The rear brake pedal length has been extended by 10 mm while the diameter of the rear brake caliper piston has been reduced from 26 to 24 mm.
Other details include, KTM’s ‘No Dirt’ footpegs - 6 mm higher than the SX versions - stiffer radiators, 9.5L fuel tank, new seat design, new air box design, 2017 graphics, Neken handlebars, speedometer.