FX 350 Heritage 2025

01. Faster and wiser

Engine

The engine is designed to deliver maximum performance with all major engine components and shaft arrangements positioned to enhance overall handling. Weighing just 27.2 kg, the 350 cc 4-stroke engine centralises mass and aids the anti-squat behaviour of the whole chassis.

Cylinder head

The DOHC cylinder head offers improved durability and serviceability, with diamond-like carbon (DLC) coated finger followers that guarantee minimal friction and optimal performance. These actuate large titanium valves, 36.3 mm for the intake and 29.1 mm for the exhaust, which optimise gas flow for strong, usable power across the rev-range, all the way up to the 13,400 rpm limit. Valve timings work in perfect harmony with the camshaft, which features a bearing bridge design for stiffness and easy serviceability.

Cylinder and piston

A large 88 mm bore and 57.5 mm stroke cylinder is professionally engineered from high-strength aluminium for maximum reliability, and houses the high performance forged bridged-box-type piston from CP. The compression ratio is 14.6:1 for exceptional torque and peak power. Engine response is strong thanks to optimised valve guides and valve shaft diameters that are precisely engineered using computational fluid dynamics (CFD).

Crankshaft

At the centre of the high-output, high-revving engine is a crankshaft featuring a plain big end bearing rotating on two force-fitted bearing shells. Ensuring maximum reliability and durability, the crankshaft offers long service intervals of 90 hours.

Crankcases

Designed for optimised mass centralisation, the crankcases house all internal components in the perfect position to achieve the ideal centre of gravity. Manufactured using a high-pressure die cast production process, the result is a thin, exceptionally strong wall thickness at the lowest possible weight.

DS clutch

The FX 350 Heritage model features a durable diaphragm steel (DS) clutch. Engineered from a single piece of CNC-machined steel, the clutch basket uses thin steel plates, which contribute to the compact design of the engine.

Gearbox

Produced by Pankl Racing Systems, the 6-speed gearbox is designed to be extremely light and durable while featuring optimised and proven motocross-specific gear ratios (24:72). Integrated into the shift drum, a Quickshifter sensor can be activated by pressing the QS marked button on the Map Select Switch to further aid smooth upshifting.

Engine

Cylinder head

Cylinder and piston

Crankshaft

Crankcases

DS clutch

Gearbox

02. Ride easier

Frame

All Heritage models benefit from an advanced frame that is engineered with specific wall thicknesses in high stress areas for strength and a calculated level of flex. Overall, the chassis offers exceptional cornering agility, unparalleled rider feedback, energy absorption, and confidence-inspiring straight-line stability. The frame is finished with a premium white powder coating, unique to the Heritage models, with frame protectors offering superior protection, durability, and grip in any condition.

Polyamide-reinforced aluminium subframe

Made from 60% polyamide and 40% aluminium, the two-piece subframe ensures exceptional strength and durability at an overall weight of just 1.8 kg. The lower subframe spars and frame mounts are manufactured from cast aluminium for maximum reliability. The upper section of the subframe is made from injection-moulded polyamide to enable specific flex characteristics and ensure a lightweight construction.

CNC machined triple clamps

Working in unison with the frame design and suspension set-up, the CNC-machined triple clamps ensure precisely calculated geometry for assured stability. Handlebar flex can be customised with the handlebar clamp, which offers two mounting options - rubber-damped for less vibration, or fixed for enhanced front-end feedback. The upper triple clamp is stiffer to ensure a smoother fork action and plays a vital role in the perfect alignment of the front wheel for superior handling.

WP XACT front suspension

Rigorously tested by WP's research and development department, the 48 mm WP XACT closed cartridge spring forks fitted to the TX 300 Heritage model provide exceptional comfort. Inside the forks, mid-valve pistons optimise oil flow and prevent foaming for consistent and predictable damping at all times. A hydrostop, active in the final 68 mm of travel, reduces the impact of harsh and high-speed landings for continued straight line stability and forward momentum. Both the compression and rebound settings can be quickly adjusted by hand using the easy access clickers. Additionally, the pump needed to adjust the air spring pressure in the forks is provided with each Heritage machine.

WP XACT rear suspension

Inside the WP XACT rear shock is a Computational Fluid Dynamics (CFD) optimised main piston for exceptional comfort with the overall design of the shock providing strong hold-up in all conditions. The linkage system features low-friction seals for unrestricted suspension performance with a lightweight bolt utilised to save weight. Rebound and high and low speed compression settings can be easily adjusted by hand to simplify any set-up changes.

Swingarm

The swingarm is manufactured using a die-cast production process for optimal rigidity. To optimise and match the flex characteristics of the chassis, a 22 mm rear axle is utilised. Additionally, the chain slider is exceptionally durable while the chain guide is manufactured with a rounded profile to ensure it is less prone to catching on external objects.

Frame

Polyamide-reinforced aluminium subframe

CNC machined triple clamps

WP XACT front suspension

WP XACT rear suspension

Swingarm

03. Effortless ergonomics

Bodywork

The bodywork has been designed to allow riders to perform at their very best for extended periods of time with the distinctive blue radiator shrouds unique to the Heritage models. Following countless hours of testing and refinements, the large contact points and surfaces in the rider triangle enhance comfort, which in turn helps to reduce fatigue. A flat seat profile allows for unrestricted movement while the blue, high-grip seat cover ensures riders stay firmly in place under hard acceleration.

Tool-less airbox

A strong, one-piece airbox with optimised air intake tracts ensure an unrestricted flow of air for maximum power. The Twin Air filter is easily accessed without tools, by simply removing the left side panel for easy maintenance.

Hydraulic clutch

The high-performance Brembo hydraulic clutch system guarantees even wear, near maintenance-free operation, and perfect action in every condition. With this hydraulic system, free play is constantly compensated so that the pressure point and function of the clutch remain identical in cold or hot conditions, as well as over time. Countless hours of race-focused testing have proven the exceptional reliability of the high-quality, Italian-made Brembo hydraulic systems.

Hydraulic brakes

The highest levels of quality and performance are guaranteed as the class leading Brembo brake calipers are made from single pieces of aluminium for exceptional strength at the lowest possible weight. Together with a 260 mm front and a 220 mm rear disc, which are designed to prevent mud build-up, superior stopping power and braking confidence is guaranteed in all conditions.

ProTaper handlebar

Developed between Husqvarna Mobility and leading handlebar manufacturer, ProTaper, the exclusive bend offers superior comfort, class-leading strength, and fatigue resistance at the lowest possible weight.

ODI grips

ODI lock-on grips feature an innovative, integrated throttle mechanism and are installed without using glue. The throttle assembly offers easy free-play adjustment with the option to fit alternative cams for a personalised throttle action.

Footrests

The CFD-designed footrests are extra wide to ensure better control of the machine while at the same time they are less susceptible to catching on deep ruts, take-offs when scrubbing, and trackside barriers. This was achieved by the narrow mounting design in the frame layout.

Bodywork

Tool-less airbox

Hydraulic clutch

Hydraulic brakes

ProTaper handlebar

ODI grips

Footrests

04. Master your art

Wheels and tyres

Assembled with CNC-machined hubs, lightweight spokes, and strong, black-anodised alloy rims by D.I.D, the Heritage model wheels offer strength and minimal unsprung weight. A Dunlop Geomax MX33 Motocross tyre is fitted to the front wheel with a Dunlop Geomax AT 81 tyre on the rear. This tyre combination ensures progressive cornering and superior traction across a variety of terrain.

Exhaust system

The exhaust system on the FC 350 Heritage model features a flow-designed resonance chamber, which plays a vital role in delivering class-leading performance. Manufactured in two pieces and designed to be as compact as possible, the header pipe allows for the system to be removed without removing the rear shock. The silencer has a short and efficient design, moving weight closer to the centre of gravity and ensuring impressive power while keeping noise as low as possible. A black coating highlights the premium quality of the silencer.

Cooling system

Manufactured from high-strength aluminium, the radiators are designed using computational fluid dynamics (CFD) to channel air through them in the most effective way. A large centre tube through the frame reduces pressure at this point in the system for a consistent coolant flow while an internal thermostat further enhances reliability.

Fuel tank

An 8.5 litre fuel tank integrates neatly with the ergonomic bodywork and features a strong rubber cushion beneath it to protect the white frame from wear. A one-piece fuel pump with integrated filter allows the tank to be emptied further for extended running times. For durability, the external fuel line is specifically routed to make it less exposed and susceptible to damage.

Wheels and tyres

Exhaust system

Cooling system

Fuel tank

05. Technologically advanced

Map select switch

The intuitive handlebar-mounted Map Select Switch allows riders to activate Launch and Traction Control, enable the Quickshifter, and allows riders to toggle between two engine maps. The easy-to-operate Map Select Switch allows racers to quickly alter and set up the engine characteristics on a race by race basis dependent on track conditions and rider preference.

Quickshifter

The Quickshifter function can be activated or deactivated via the Map Select Switch and works by interrupting the ignition for a fraction of a second when upshifting. A sensor on the shift drum registers the force from the shift lever, sends a signal to the ECU, and ensures smooth gear changes, even when the throttle is fully open. To prevent unintended shifts, the function is only active from second gear upwards.

Traction Control

Traction Control on the FX 350 Heritage model is engaged by pressing a button marked 'TC' on the Map Select Switch and functions by analysing throttle input from the rider and the rate at which engine RPM increases. If the RPM increases too quickly, the engine management system (EMS) registers a loss of grip and reduces the amount of power to the rear wheel to ensure maximum traction. This is a distinct advantage in wet or muddy conditions.

Mapping

By using the Map Select Switch, the engine characteristics can be tailored to modify the power delivery according to rider preference, conditions, and terrain. It has two settings that can be safely toggled between while riding, by simply pressing a button on the handlebar-mounted Map Select Switch. Map 1 (white) is the standard option, that delivers linear, predictable power, while map 2 (green) is more aggressive with improved throttle response and sharper, explosive power output.

Engine management system

The Keihin engine management system (EMS) is designed to be small, light, and fast at processing data. It incorporates a rollover sensor (ROS) which cuts the ignition and shuts off the engine in the event of a severe crash for an additional layer of safety.

Hour meter

The engine management system (EMS) is designed to be small, light, and fast at processing data. It incorporates a rollover sensor (ROS) which cuts the ignition and shuts off the engine in the event of a severe crash for an additional layer of safety.

Start/stop switch

The hour meter comes with an integrated fuel level indicator, which is visible on the FI status LED, and warns the rider when the fuel level is becoming low.

E-Start

The combined engine start/stop switch is located on the right side of the handlebar for easy, thumb-operated use. Not only simplifying the starting and stopping of the engine, but the removal of an additional stop only button from the handlebar reduces the risk of potential damage or activation in the event of a fall.

Map select switch

Quickshifter

Traction Control

Mapping

Engine management system

Hour meter

Start/stop switch

The hour meter comes with an integrated fuel level indicator, which is visible on the FI status LED, and warns the rider when the fuel level is becoming low.

E-Start

FX 350 Heritage 2025

01. Faster and wiser

Engine

Cylinder head

Cylinder and piston

Crankshaft

Crankcases

DS clutch

Gearbox

Engine

Cylinder head

Cylinder and piston

Crankshaft

Crankcases

DS clutch

Gearbox

02. Ride easier

Frame

Polyamide-reinforced aluminium subframe

CNC machined triple clamps

WP XACT front suspension

WP XACT rear suspension

Swingarm

Frame

Polyamide-reinforced aluminium subframe

CNC machined triple clamps

WP XACT front suspension

WP XACT rear suspension

Swingarm

03. Effortless ergonomics

Bodywork

Tool-less airbox

Hydraulic clutch

Hydraulic brakes

ProTaper handlebar

ODI grips

Footrests

Bodywork

Tool-less airbox

Hydraulic clutch

Hydraulic brakes

ProTaper handlebar

ODI grips

Footrests

04. Master your art

Wheels and tyres

Exhaust system

Cooling system

Fuel tank

Wheels and tyres

Exhaust system

Cooling system

Fuel tank

05. Technologically advanced

Map select switch

Quickshifter

Traction Control

Mapping

Engine management system

Hour meter

Start/stop switch

E-Start

Map select switch

Quickshifter

Traction Control

Mapping

Engine management system

Hour meter

Start/stop switch

E-Start

Technical Details

Engine

Chassis