The 2011 KTM 150SX Dirt Bike

2011 KTM SX Chassis and Frame – Completely new frames, made of modern lightweight chrome-moly steel material in various profiles.

Compared to KTM’s previous SX frames the MY 2011 frame design provides higher torsional and reduced longitudinal stiffness.

Air flow optimized intake boot between filter and carburetor

In addition it is designed to absorb energy created from the rear wheel impacts.

This new design benefits both the PDS of the new 2-strokes and Pro-Lever Linkage rear suspension of the 4-strokes.

The basic frame designs are pretty much the same. The main difference between PDS and linkage is the tower of the upper shock mount, which for both systems, takes the main role to isolate the shock absorber forces from the frame.

To the aluminium frame trend of our competitors, we have delivered a high-tech steel frame that weighs less than the lightest competitor.

In addition it is easier to maintain, easier to work on and supplies more space for the tank and other components.

Rear Suspension – KTM has proven that the PDS rear suspension system is capable of wining any motocross race. But when it comes to Supercross the PDS becomes more critical in regards to bike set-up. The linkage provides a better solution to the increased loading demands that extreme Supercross requires and covers a wider range of circuits.

Both systems have a certain rising rate, which means that when the rear wheel moves at a constant rate, the rate of the shock shaft increases, or in other terms, if the rear wheel travels at a constant velocity, the shock shaft is accelerating. The difference between the two systems is with PDS the shaft velocity does not increase as much as with linkage.

The PDS system creates additional damping with internal systems in the shock, and as a result, both the linkage and PDS system produce similar dampening characteristics. The main difference then lies in the fact that the PDS system provides a more linear spring progression than the linkage system. The PDS character is extremely beneficial for the lighter 2-stroke bikes and to off-road applications, whereas a high spring progression in the linkage system benefits the extreme Motocross and Supercross applications.

Shock – PDS 2011: Longer PDS shock to offer an improved rising rate character.

Linkage: Completely new WP unit with piston and bushings that provide better seal and friction properties to handle the higher shaft velocities. Both shocks also have a new spring retention and preload system to allow for preload adjustment without the use of hammer and punch. A wide range of adjustability of rebound and high/-low speed compression damping are KTM standard anyway.

Why PDS for the 2-strokes? The directly linked PDS shock has turned out to be the best solution for the 2-strokes. 2-Strokes have a totally different engine characteristic than 4-strokes and also a different centre of gravity. Many tests have proven that the PDS rear suspension fits better to the lighter and more nervous characteristics of the 2-strokes. With the lighter PDS system, the 2-strokes will keep a major weight benefit, also in the future.

The 150 XC has a higher fourth, fifth and sixth gear compared to its moto-focused 150 SX sibling.

Will PDS remain for the XC/XC-W/EXC line-up?Yes – no doubt about it! The majority of the Enduro applications benefits from the more linear spring progression of the PDS. In addition, it provides a better ground clearance, less maintenance, less weight and easy access to remove the shock from the bike within a few seconds.

Swingarm – New cast aluminium swing arms for both the PDS and the linkage. The single-component casting process allows unlimited geometry solutions and eliminates any inconsistencies created by welding. Updated mounting positions, higher profiles and optimized flex are supporting the frame and suspension characteristics.

Front Suspension – All SX models are fitted with the latest generation of 48 mm USD front forks “made by WP in Austria”. Due to intense development in the recent years the “WP closed cartridge technology” has been fine-tuned for excellent sensitivity and damping characteristics, which has been proven in many of last year’s shootouts. For MY 2011 new settings for each model perfectly matches the needs of the new chassis packages.

Triple Clamps – The KTM patented SX triple clamps are a “work of art”. CNC machined out of high quality aluminium blocks the sophisticated design and clamping avoids squeezing of the tubes and supports fork action. In addition, the design provides a certain flex, which allows the triple clamps to follow the fork legs when deflected during hard landing or braking.

Bodywork – According to KTMs philosophy Design follows function, the engineers put highest priority on rider ergonomics. And in this respect Stefan Everts took a key roll during the entire development process. Who could know the needs of a motocrosser better than a 10 time MX world champion? From the first clay model till the final product Stefan was heavily involved with each step of the development and he really pushed the design team of Kiska until every single detail was addressed in order to get the ideal shape of a future champions bike. The results are super slim ergonomics and a bodywork with excellent contact points between rider and machine. He also insisted on having a wider and 50 mm longer rear fender. And not to forget features like the no-tools access to the air filter or the incorporated lift handle in the outer rear fender, which is well protected against dirt from the rear wheel.

Airbox – The new layout of the airbox was driven by two main functions: optimised protection for the air filter against dirt and a maximum airflow for maximum performance. Due to the special design between filter and intake throttle body, the airbox was designed separately for every displacement and improves the power significantly. The ability to change the large Twin-Air filter quickly and without tools is the KTM standard and outstanding in the motocross world.

Wheels – Weight reduced high-quality wheels with CNC machined hubs and high-end EXCEL rims are hard to beat and remain the standard in terms of durability. New silver rims do not only appear lighter, they also take the unavoidable damages during tire changes much better than rims coated in any other color. Spokes are now covered with a noble zinc-/ nickel coating which not only suits the silver rims optically, but also has an improvement regarding corrosion resistance. New nipples made of high-strength aluminium the weight could be reduced again, which is an important feature supporting suspension action and easy handling.

Exhaust Silencer – The 4 strokes have new improved silencers that score points with a modern and voluminous profile not only optically but also reducing the noise level to future noise emission regulations (115dB(A)). A bigger outlet diameter improves the performance and delivers a sound improvement. New silencers for 2 stroke bikes introduce a new “two-component” technology. A strong plastic holder is injection-molded around the aluminium housing to attach the silencer to the motorcycle better.

Cooling System – The proven integrated cooling system routes from the cylinder head through the frame triangle directly to the radiators, the removed tubing simplifies the radiator mounting and improves the air flow through the radiators. A new T-connector with an optimised fluid flow improves the heat dissipation.

Fuel Tank – The slim 7,5 litre tank made from lightweight polyethylene includes a compact fuel pump at 250/350 SX-F models. All other models introduce a new fuel tank with the same capacity as well. The well proven ¼-turn fuel cap allows easy and quick refilling and includes a security against unwanted turning.

Brakes – Brakes by Brembo are serial equipment of KTM models and are combined with lightweight wave rotors which are the benchmark when it comes to feel and brake performance.

Hi-End Equipment, Standard – No change here. KTM has always been known for including only the best equipment available as standard OEM. There are many features on the new SX which highlight the KTM at first appearance against its competitors. For example, the comfortable hydraulic clutch, tapered Renthal handlebar or CNC machined triple clamps, Twin Air air filter, high grade chain and sprockets, Also smaller details like footbrake lever with a high quality bearing

The perfect combination of playful handling of a 125 and engine power close to a 250 4 stroke. In many countries the 150 SX can be raced in MX2 class and becomes increasingly an alternative for all who like the easiest handling and reasonable costs.

In addition to the unique engine concept, the MX lineup for the 2011 also includes a newly developed frame and chassis components.

If you enjoy reading our Articles, please consider leaving a comment or subscribing to the RSS feed to have future articles and News information on Motorcycles delivered to your feed reader. Thank you and have a great day!

Comments are closed.