has released its 2011 line of dirt bikes and the new model year brings big technological changes. PDS suspension has been a defining characteristic of the Austrian brand for years – probably the defining characteristic. After years of defending the linkage-less shock design, KTM has finally conceded that a linked system works better for motocross and Supercross applications. Spearheaded by the introduction of the all-new 350 SX-F, every SX-F model will come with the new shock while the 2-strokes retain the PDS. Fuel injection also comes to the table as well as a list of smaller updates across the motocross range.
2011 KTM 350 SX-F
The KTM 350 SX-F is finally here. Fuel injection, electric start and a linkage shock top a long list of highlights.
The new 350 is one of the most highly anticipated machines in the past decade, and for good reason. This is the first “in-between” motocross bike which could potentially fill a huge void that is created by the nimble but underpowered 250s and overbearing 450s. KTM has blended some of its favorite traits with new technology to create what it’s touting as the perfect motorcycle. With 10-time World Motocross champion, Stefan Everts, at the helm, maybe it’s not such a far-fetched claim.
For the first time on a dirt bike, KTM is using fuel injection with 42mm throttle body and a Keihin engine management system on the 350. Like other orange bikes, alternate engine maps are available with the use of a switch available from the KTM PowerParts catalog. The EFI system adjusts for changes in temperature and elevation to ensure proper fueling. It also features an automated cold start – which leads into the next awesome tidbit. The 350 will be electric start, but it has the ability to mount a kick start as well, giving riders plenty of options (good job, KTM). From our experience, even if the foot lever is available, nobody will ever use it as long as the magic button is available. KTM has proven its motocross bikes to be excellent e-starters with the 450 SX-F.
A five-speed transmission operated by hydraulic Brembo clutch manages the power output from the DOHC single-cylinder engine. The 349.5cc mill uses four titanium valves with a claimed rev limit of 13,000 rpm. Bore and stroke are 88 x 57.5mm compared to 76 x 54.8mm on the 250 and 97 x 60.8mm on the 450.
The 350 SX-F uses a DOHC engine with four titanium valves with
Keihin engine management system and 42mm throttle body.
KTM retains its chromoly frame design, but have made changes which increase torsional rigidity and lessen longitudinal stiffness. The frames only differ between PDS and the new linkage shock in the mounting points.
Yes, you read that correctly, KTM now has a linkage. Adding a linkage allows the shock shaft to move more quickly through its rising rate. This “high spring progression” is preferred for the increased loads associated with MX and SX. Off-road models and the 2-stroke SX machines will still come with the PDS version (now longer), where KTM claims the technology is still superior. Both types of shock absorber are manufactured by WP and have KTM’s user-friendly shock collar for simple preload adjustment. Both shock types require a new cast aluminum swingarm with updated mounting positions.
All SX-F models also get the latest generation 48mm WP fork to pair with the new triple clamps from 2010. Settings on the closed-cartridge fork are tailored to match the chassis and new shock, but the fork is relatively unchanged.
KTM has stressed the importance of making the 350 handle like a 250, and has focused on the ergonomics. A thin layout over the two-gallon fuel tank and particular attention paid to the contact points promise a nimble-handling machine. Stylistically, the rear fender is wider and 50mm longer. The new models also trade their black rims for silver.
2011 KTM 350 SX-F Video
2011 KTM 450 SX-F
The 2011 450 SX-F retains it 41mm Keihin carburetor – though who can argue after it won out 2010 450 Motocross Shootout
against a slew of EFI machines.
2011 KTM 250 SX-F
While the 450 is relatively unchanged, the 250 SX-F gets major updates as well.Bottom:
KTM still offers 2-stroke fun with the small-but-potent 150 SX.
The quarter-liter machine is the other KTM dirt bike to receive fuel injection – opposite of the Japanese brands which have converted the 450 machines first. New camshafts and valve timing handle the new fueling system and updated intake port, intake boot and exhaust. The header is redesigned and the muffler outlet is larger for better exhaust flow. The 2011 KTM 250 SX-F is kick start, but has been modified this year to allow for a conversion to e-start if desired using a PowerParts kit with starter, ignition cover, gears, battery and wiring.
2011 KTM 250 SX
KTM continues to keep the 2-strokes alive and well, not only by refusing to axe them from the lineup, but by actually improving the design each year. For 2011, the 250 SX has the new PDS chassis with a revised airbox. The exhaust pipe is updated and matches the changes to the cylinder, including lower exhaust ports and new timing. A two-part silencer uses plastic injection molded around the aluminum housing for better attachment.
2011 KTM 150 SX
The small-bore smoker is back again for all the light-handling, zippy fun. It too gets the new PDS chassis and two-part silencer