If you’re reading this, then it is safe to say things have become
serious. The 2024 KTM 85 SX is the first real step into the big leagues.
Lightweight, powerful and reliable, the KTM 85 SX boasts real big bike
components in scaled-down 85 cc geometry, providing the ultimate
kickstart to any young racing career.
It took extreme levels of ingenuity to fit the race-winning formula of KTM’s bigger 2-strokes into a compact 85 cc engine. The super-compact powerplant is fitted with a 6-speed gearbox and delivers class-leading power and rideability throughout the entire rev range. The powervalve plays a key role in tailoring power delivery to suit track conditions and rider ability, ensuring that the only rider surprised by the incredible performance is the competition.
The cylinder on the KTM 85 SX has a bore and stroke of 47mm and 48.95 mm respectively. It features a sophisticated power valve system, which controls both the exhaust valve and the sub exhaust ports, giving the bike excellent torque and power delivery. This translates into significant midrange performance, reducing the need to overwork the clutch in loamy or sandy conditions. An adjuster screw allows the opening time of the power valve to be adjusted to suit rider preference and track conditions.
CRANK CASES & ENGINE COVER
The crankcases are manufactured using a high-pressure die-cast production process, keeping wall thickness to a minimum while retaining strength and durability. The design of the cases is very compact and aims at positioning the shaft arrangements as close as possible to the center of gravity, contributing to better handling.
The KTM 85 SX features a lightweight 6-speed gearbox, engineered to take a beating. The gear ratios have been developed to perfectly match the characteristics of the engine, with easy and precise shifting allowing the rider to slot in the next gear quickly and confidently. The gearbox also features a driveshaft that uses a screw to secure the front sprocket, and a diaphragm spring instead of a circlip, to ensure the front sprocket remains firmly in place. As with all KTM SX models, the KTM 85 SX transmission has a “no-dirt” gear shifter which, like the footpeg design, prevents dirt build-up.
Ultra-durable thanks to modified clutch components, the 2024 KTM 85 SX allows riders to actuate the clutch level with ease, thanks to the FORMULA hydraulic system, which conveniently ensures that play is always compensated for. This means the clutch “bite” point remains consistent throughout the ride and under all conditions.
The KTM 85 SX is fitted with a MIKUNI TMX carburetor. This 38mm flat slide carb lives to provide smooth and controllable power all the way up to the rev limitation. The angle of the intake manifold helps to reduce the overflow of fuel. It’s also less sensitive to different altitudes and temperatures, so you can pin it wherever, whenever.
The KTM 85 SX features a lightweight crankshaft with optimized balancing for reduced vibration and oscillating mass. As light as the crankshaft is, the rotational inertia has not been compromised, ensuring maximum torque and revs, as well as easy rideability.
Maintaining the optimal engine temperature is crucial to ensuring consistent horsepower throughout the ride. The KTM 85 SX features radiators which are positioned for a lower center of gravity. Their design matches the shrouds perfectly and offers a great slim feel to the ergonomics. By using CFD technology (computational fluid dynamics) together with a clever coolant circuit routing, the innovative system ensures the optimum engine temperature for the highest performance, no matter what the conditions. The radiators also feature special protectors that serve not only as protection from flying rocks and debris but also as a brace that disperses energy around the radiators in the event of an impact.
The exhaust system has been designed to perfectly match the engine’s power characteristics and contributes to the outstanding all-round performance and rideability. The header pipe is produced using a 3-dimensional stamping process. Once the components have been shaped, they are robot welded to ensure the highest level of quality, consistency and durability. The lightweight and compact silencer has been reworked with improved packing wool (40 g lighter), guaranteeing that sweet 2-stroke sound and falling safely within the noise limits for racing.
The frame on the KTM 85 SX is a scaled-down version of the multi-championship-winning full-size frames. Made from hydroformed chromium-molybdenum steel tubes that are robot welded, the frame is pin-point accurate, ensuring the highest levels of consistent quality and flex characteristics.
The 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.
The 2024 KTM 85 SX features a ‘big wheel’ Excel rim combo powdercoated in black, with a 17-inch front wheel and a 14-inch rear. These are mounted on CNC-machined hubs and wrapped in MAXXIS MX-ST tires which deliver exceptional straight-line stability and excellent traction when chasing the holeshot.
The KTM 85 SX front fork features the same suspension technology found in the full-size motocross range. The WP XACT AER fork consists of a split fork design with a capsuled air spring in the left leg and the trusted oil damping system in the right leg. It offers a significant reduction of 1.0 kg in weight over conventional spring forks. Importantly, the preload adjustment is extremely simple and can be adjusted by using the single air pressure valve and supplied air pump. The design also allows for easy access to compression and rebound clickers.
The KTM 85 SX features a WP XACT PDS (Progressive Damping System) rear shock absorber. The design offers a high progression rate and excellent response. It allows an impressive 305 mm of rear wheel travel and is fully adjustable for preload, compression and rebound.
Bringing this little screamer to a stop is down to the Formula brake system with radial calipers – four pistons in front, two in the rear – with lightweight Wave brake discs. The system is the benchmark in terms of controlled action and braking performance, ensuring powerful and confident braking.
The KTM 85 SX airbox is a masterclass in design, optimizing the tiny space available to deliver the best possible performance, while still maintaining the highest level of filter protection. The air filter is easily accessed, without tools, by removing the left side panel. The Twin Air filter and filter cage design feature a simple, secure mounting system, making filter maintenance quick and easy, which means less time in the pits, and more time winning races.
Holding approximately 5.2 litres of pre-mixed fury, the tank is perfectly shaped to be small and slim to allow for easy and uninhibited rider movement, while still providing enough range to cover a full race at full throttle.
Hang on tight – the KTM 85 SX features a strong, lightweight, tapered aluminum handlebar, with a specifically shaped bend to suit its overall ergonomics. Additionally, the bike comes standard with ODI lock-on grips, which include a vulcanized grip on the right side and a lock-on grip on the left that do not require glue or wire for mounting.
The KTM 85 SX has “no-dirt” footpegs, which have a simple but effective self-cleaning system that ensures the footpegs return to their original position, providing complete control in all conditions.
Providing the perfect blend of grip, durability and comfort, the 2023 KTM 85 SX seat does everything you’d expect it to, while showing off it’s its undeniable READY TO RACE and ‘orange’ heritage.