Engine management system (EMS)
The Keihin EMS is specifically designed to be smaller, lighter and faster at processing data. It integrates launch control for perfect starts, selectable engine maps via the traction control switch on the handlebar as well as the Easy Shift function. Combined with the gear sensor, power delivery is tailored for each gear.
A new rollover sensor (ROS) cuts the ignition in case of extreme crashes, adding another level of safety to the new generation of Husqvarna motocross machines. Additionally, the new hour meter now comes with an integrated FI status LED and a fuel level indicator.
- Keihin EMS → small, light and faster at processing engine data for more efficient engine management
- New rollover sensor (ROS) → automatic cutting of ignition in extreme crashes
- New hour meter with integrated FI status LED and fuel level indicator
- Gear sensor → specific engine maps for each gear
44 mm throttle body
The Rockstar Edition models feature a 44 mm Keihin throttle body. The injector is positioned to ensure the most efficient flow into the combustion chamber, and to ensure optimal throttle response the throttle cable is mounted directly without a linkage providing more immediate throttle response and feel.
- Throttle body → 44 mm, injector positioned for optimal flow, more immediate throttle response thanks to direct cable mounting
Exhaust system
The Rockstar Edition exhaust systems are expertly designed to deliver leading performance for the least possible weight. The header pipe features a flow-designed resonance chamber integrated into the header pipe. The header pipe is designed and manufactured in two pieces to be as compact as possible. The position of the join allows it to be removed without having to remove the rear shock. Further innovation allows for a short, compact silencer without increased noise levels. The silencer is crafted from lightweight aluminum and is stylishly finished in a black coating that highlights its premium quality.
- Compact exhausts → lightweight and engineered for optimal performance
- Header pipe mounted directly onto engine mount for improved serviceability
- Header join position → removal of exhaust without removing rear shock
Electric start and Li-Ion battery
To deliver the benefit of an easy electric starting system, a Li-Ion 2.0 Ah battery is fitted to the Rockstar Edition models. The Li-Ion battery weighs approximately 2.2 lb (1 kg) less than a conventional lead/acid battery, so the convenience of electric starting is delivered while minimizing overall weight.
- Electric starter → easy starting when time is critical
- Li-Ion battery → lightweight, 1 kg lighter than a conventional battery
Integrated cooling system and radiators
The radiators are expertly crafted by WP using high-strength aluminum. CFD optimization is used to channel air through the radiators more efficiently and provide optimal cooling in any condition. The cooling system is integrated into the frame allowing for improved cooling by channeling coolant through the frame while eliminating the need for additional hoses. A large center tube running through the frame reduces the pressure at this point in the system allowing for a more consistent coolant flow and now includes an internal thermostat for added reliability.
Additionally, the radiators are mounted close to the center of gravity for improved handling agility.
- Integrated cooling → maximum efficiency in minimum space
- New bayonet closure radiator caps
- WP radiators → efficient for optimal cooling
- Large central tube → consistent coolant flow
Fuel tank
The new 1.9 gallon (7.2 liter) polythene fuel tanks incorporate a threaded filler cap and an integrated fuel pump on the Rockstar Edition models. A new one-piece fuel pump with integrated filter provides improved fuel supply and allows the tank to be emptied further at low fuel levels. The external fuel line is specifically positioned to make it less exposed and susceptible to damage.
- New 1.9 gallon (7.2 liter) polythene fuel tanks → larger capacity for extended running times
- New one-piece fuel pump and filter for improved fuel supply → tank can be emptied further at low fuel levels
- External fuel line routing → less exposed and susceptible to damage
Airbox and tool-less air filter access
The CFD optimized airbox is designed with precisely positioned inlet ducts to prevent air deformation and ensure maximum airflow and filter protection. The air filter is easily accessed, without tools, by removing the left side panel. Easy maintenance is guaranteed by the Twin Air filter element and filter cage design, featuring a simple fail-proof mounting system for safe and accurate filter installation.
- CFD optimized airbox → improved air flow and maximized filter protection
- Intuitive filter mounting system → safe and accurate protection against dirt
- Tool-less filter access → quick and easy maintenance
- High-flow airbox cover in the by-pack → added customizability of the engine response
Factory wheel set
Black high-strength anodized DirtStar rims by D.I.D are laced to high quality black anodized CNC-machined hubs, using lightweight spokes and black anodized aluminum nipples to offer maximum weight savings and optimized handling and stability in the most extreme motocross conditions.
- Lightweight but strong and reliable construction → minimal unsprung weight
Tires
Dunlop GEOMAX MX33 Motocross tires featuring the proven ‘block-within-a-block’ design for more progressive cornering and superior grip are fitted as standard.
- Developed in top-level AMA Supercross and Motocross → enhanced handling, cornering and steering feel
- Wide range of application including sand, mud, loose surface, and hard pack
- Increased durability and crack resistance through an innovative rubber compound
Bodywork
The Rockstar Edition models feature bodywork which clearly showcases Husqvarna Motorcycles progressive approach to off-road motorcycles and striking black-and-white graphics stylishly adorn the Swedish-inspired design.
An improved rider triangle for better knee contact, especially when riding in the standing position, inspires confidence for riders of every ability and enables them to perform at the highest level for extended periods of time. The slim contact surfaces on the bodywork allow the rider to more easily move the bike around on track, and improve the overall handling and agility of the bike.
The flat seat profile, combined with the race engineered GUTS high-grip seat cover, deliver superior control in all conditions. A recessed pocket under the seat, just above the airbox, allows gripping and lifting of the bike.
The graphics of the all-new Rockstar Editions closely resemble the look of Husqvarna’s Factory race bikes for the 2022 season. Sponsor logos and graphic design elements are implemented using durable in-mold technology. A high-quality factory race look is guaranteed, even after hours of intense riding.
- Progressive bodywork → distinctive looks, modern design and graphics
- Improved rider triangle for better knee contact, especially when riding in the standing position
- Additional contact surface → allows for improved gripping and easier movement of the bike
- Recessed grip pockets → allowing better grip to lift the bike
- Seat → flat seat profile and high-grip Factory seat cover for exceptional comfort and control in all conditions
Technical details by model
FC 250 Rockstar Edition
Engine
The newly designed FC 250 Rockstar Edition engine is tilted 2° backwards and therefore comes with a repositioned sprocket which is 3 mm lower compared to the previous generation. The total engine height has been reduced by 8 mm to improve mass centralization and reduce weight (approx. 60 g).
Added service markers on the engine (▲) clearly show where to use washers, making maintenance and service easier than in the past.
All major components and shaft arrangements are carefully designed and placed to best suit the performance and handling characteristics of the overall package, and an added benefit of this new design is improved anti-squat behavior from the whole chassis.
The 250cc engine is not only light at 57.5 lb (26.11 kg) but also remarkably powerful with reworked midrange.
- New engine design → light and compact for optimized mass centralization
- Engine tilted 2° backwards with repositioned sprocket (3 mm lower)
- Improved anti-squat chassis behavior
- Engine height reduced by 8 mm for improved mass centralization reduced weight (approx. 60 g)
- Low-friction design → reduces overall drag and vibration
- Outstanding high-revving performance engine → enhanced midrange
- Improved serviceability of engine internals with added service markers
Cylinder head
The fully redesigned DOHC cylinder head features finger followers with a DLC (diamond like carbon) coating resulting in minimal friction and optimal performance. These actuate large titanium valves (32.5 mm intake, 27.5 mm exhaust) which at the 14,000 rpm rev limit open and close multiple times every second introducing fuel/air mixture to the carefully designed combustion chamber to deliver efficient and optimal power throughout the rev-range.
The new 27.5 mm exhaust valve is a result of the new bore/stroke ratio, delivering an optimized gas flow. Valve timings have been adapted to the new valve measurements, working in perfect harmony with the redesigned camshaft.
For improved serviceability and maintenance work within the engine, the redesigned adjustment bush bridge is screwed and increases stiffness. Also, the head gasket comes with a new ‘stopper design’, reducing sealing gap oscillations caused by gas force.
- Fully redesigned cylinder head → improved durability and serviceability
- Finger followers with DLC coating → reduce friction and guarantee optimal performance
- Large titanium valves (32.5 mm intake, 27.5 mm exhaust) with new 27.5 mm exhaust valve → optimized gas flow with revised bore/stroke ratio
- Redesigned camshaft → adapted valve timing to new valve measurements
- New adjustment bush bridge increasing stiffness and improving serviceability (screwed design)
- New cylinder head gasket with stopper design → reducing sealing gap oscillations caused by gas force
Cylinder and piston
The new 81 mm bore cylinder houses a forged bridged-box-type piston made by CP with an extremely light weight of only 150 g. Both the cylinder and piston are professionally engineered from high-strength aluminum resulting in outstanding performance and reliability. The stroke has been adapted to 48.5 mm and the compression ratio has been increased to 14.5:1 for added torque and peak performance.
Thanks to the CFD optimized combustion chamber, the inlet port could be smaller in section resulting in improved engine responsiveness.
- New 81 mm bore and 48.5 mm stroke (MY22 = 78/52.3 mm)
- Larger 81 mm bore and larger diameter exhaust valves → high-revving, quick response
- CFD optimized combustion chamber → smaller inlet port for improved engine responsiveness
- Compression ratio increased to 14.5:1 → greater torque and peak power
- Forged bridged-box-type piston → high performance and reliability
Crankshaft
The crankshaft is designed to offer the best possible performance while being perfectly positioned in the engine cases to centralize oscillating masses for optimal handling. The plain big-end bearing features two force-fitted bearing shells ensuring maximum reliability and durability, guaranteeing long service intervals of 100 hours.
- Plain big-end bearing with force-fitted bearing shells → increased durability and service intervals
- Friction bearing on the counter-balancer shaft → increased durability
Crankcases
The FC 250 Rockstar Edition engine is designed with mass centralization and weight reduction as main criteria. As a result, the crankcases have been redesigned to house the internal components of the engine in the perfect positions to achieve the ideal center of gravity while adding the least possible weight. Engine mounting points are the same as on the FC 450 engine.
The casings are manufactured using a high-pressure die-cast production process, resulting in thin wall thickness while retaining exceptional reliability.
- Light and compact crankcases → optimized mass centralization
- Redesigned engine mounting points (as on FC 450 Rockstar Edition)
- High-pressure die-cast production process → thin walls for reduced weight while maintaining strength
Gearbox
Produced by Pankl Racing Systems, the new 5-speed gearbox is designed to be extremely light and durable while featuring a 250 cc-specific ratio (24:72). A redesign of the shift shaft reduces the operating forces required for gear changes. A new Easy Shift sensor is positioned on the shift drum, allowing clutchless upshifts. The function can be activated/deactivated via the new QS marked button on the map select switch, located on the left side of the handlebar.
The shift fork has a low-friction coating for smoother shifting, while the new gear lever is designed to prevent dirt build-up and ensure perfect gear selection in all conditions. An advanced gear sensor allows for specific engine maps delivering the best possible performance in each gear.
- New 5-speed gearbox by Pankl Racing Systems → 250-optimised transmission ratio (24:72) and exceptional durability and improved shifting
- Redesigned shift shaft → reduced operating force required for gear changes
- Integrated Easy Shift sensor positioned on the shift drum allows clutchless upshifts → seamless shifting function can be activated/deactivated with map select switch
- Integrated gear sensor → specific engine maps for each gear
DS clutch
The FC 250 features a DS (Diaphragm Steel) clutch. The exclusive characteristics of this system include a single diaphragm steel pressure plate instead of traditional coil springs.
The clutch basket has been revised and features the same design as on the FC 450, adapted to the new transmission ratio. It is a single-piece CNC-machined steel component that allows the use of thin steel liners and contributes to the compact design of the engine.
- New clutch basket with same design as FC 450 → adapted for new transmission ratio
- DS clutch → lightweight with consistent modulation and exceptional durability
