The 2021 KTM 350 SX-F is another one of those bikes that the Austrian company seems to have magically figured out. It is light for its size and comes packing a 349cc four-valve single, which pushes a quite astonishing 58 HP out. When the bike itself weighs a pound or two over a 250 SX-F, that extra power will definitely be noticeable.
KTM seems to have found a niche in producing bikes that don’t particularly have a motocross class of their own but are fast enough and durable enough to emulate the class above their engine size. In this case, the 350 SX-F can competently race in the 450cc four-stroke class, also known as supercross. In fact, much like some of their other bikes, racers will have a 350 SX-F as their practice bike, so that they don’t put too many hours in on their primary 450cc bike until it’s race time.
The big push with the 350 SX-F is that it, like almost all the other motocross bikes from KTM, comes packed with racing parts already on it. WP suspension, Brembo hydraulics and brakes, a wet multi-disc lightweight racing clutch, and Keihin Racing engine management. All in all, it makes a 350cc bike the master of all worlds, be it motocross, a trail ride, or cross country endurance racing and has earned its spot in the 2021 model lineup.
The 2021 KTM 350 SX-F starts at $9,999 USD / $11,399 CAD.
On this page:we’ve curated specs, features, news, photos/videos, etc. so you can read up on the new 2021 KTM 350 SX-F in one place.
The engine of the 2020 KTM 350 SX-F is neatly arranged in a compact and light (58.6 lbs) construction. It features an innovative clutch system; perfectly geared, durable transmission, and a lightweight DOHC (double overheard camshaft) cylinder head, which all contribute to making it an extremely impressive engine. It also features a new, stronger oil pump intermediate gear, for improved reliability. Fitted with the latest electronic fuel injection system and a useful electric starter, just one push of a button fires up this impressively competitive engine.
The cylinder head on the KTM 350 SX-F is the gateway to its excellent power. It features two overhead camshafts with friction-optimized super-fine surfaces, connected to DLC coated finger followers that activate four lightweight titanium valves (intake 36.3 mm, exhaust 29.1 mm). KTM engineers have maximized the flow rate, delivering an optimal power band, with outstanding performance across the entire 13,400 rpm range.
The KTM 350 SX-F’s crankshaft features a stiff design and utilizes a short, lightweight connecting rod, contributing to the incredibly dynamic and efficient power delivery. The big end bearing features two force-fitted bearing shells, which run directly on the crank pin. This design is a prerequisite for the extremely high engine speed levels and the unrivalled power of the 350 cc. The design also enhances durability, allowing for long crankshaft service intervals, resulting in less effort and cost – and more time spent on two wheels.
Crankcases and engine covers
The compact engine cases are manufactured using a high pressure die-cast production process that helps with weight reduction, while retaining strength and durability. The design allows for optimal shaft arrangements close to the center of gravity, resulting in ideal mass centralization and easier rideability. The engine covers feature a smart surface structure that reduces wear caused by the rider’s boots, keeping them looking as fresh as the day you bought it.
The KTM 350 SX-F is fitted with a robust 5-speed transmission. The gear ratios were carried over from its predecessor and are perfectly suited for the MX track. Another highlight of the transmission is the ‘no-dirt’ gear shifter. Similar to the footpeg design, it prevents the build-up of dirt and ensures the next gear is always available, no matter what the conditions.
As with the entire SX range, the frame on the KTM 350 SX-F is professionally crafted from hydroformed chromium molybdenum steel tubes that are robot welded to ensure the highest levels of consistent quality. The carefully calculated stiffness of the frame delivers responsive handling and works perfectly with the suspension to provide excellent agility and high-speed stability. All 2020 KTM SX frames feature a highly durable powder coating and come with standard frame protectors. The subframe is made from lightweight aluminum and provides great feeling for the rider, as well as easy movement across the seat.
The KTM 350 SX-F’s one-piece swingarm is manufactured using a gravity die-cast production process for exceptional strength at the lowest possible weight. It offers a wide range of adjustment for the rear wheel, allowing for a shorter wheelbase on tighter, twisty tracks, or a longer wheelbase for greater stability on longer, more choppy tracks. The swingarm’s chain measurement markings are visible from above, making adjustment simpler and more accurate.
All KTM SX models feature a seat that perfectly matches the range’s dynamic performance-oriented ergonomics. The seat cover features silicone strips that provide better feel and grip for the rider. The seat is conveniently fixed to the bike using one long, lateral screw, making it secure and easy to handle.
All SX-F models feature a capable, super lightweight 2 Ah Lithium-Ion starter battery, ensuring quick and effective starting of the engine, especially in cold weather conditions. The voltage regulator and condenser, as well as all the electrical components are packaged in a common area below the seat, making the entire system compact and reliable.