Sirris F43 CMX Fork: Arctic Leopard XE Pro S / Enduro

Upgrade your Arctic Leopard XE Pro S or Enduro with the Sirris F43 CMX Fork. Built around Sirris' oversized, race-proven F43 chassis, this 220mm travel fork combines 43mm stanchions with the CMX (Compact Motocross) closed-cartridge damping system for increased front-end control, stability, and durability during aggressive off-road riding. This Arctic Leopard version is specifically configured for the XE Pro S and Enduro with a drop clamp, dedicated wheel spacers, and 220mm brake rotor bracket for proper fitment. Important: This fork fits the Arctic Leopard XE Pro S and Enduro only. The Arctic Leopard XE Pro R requires a different F43 fork due to its brake bracket configuration and is available as a separate product. 140 lbs - 180 lbs (Medium = 4.0/3.6 springs) 180 lbs - 220 lbs (Heavy = 4.0/4.0 springs) Fork spring rates listed above are left side/right side. Sirris F43 CMX Fork Features 220mm Travel — provides substantial suspension travel for aggressive trail riding, jumps, rough terrain, and higher-speed riding Oversized 43mm Stanchions — high-tensile steel construction with hard chrome finish for increased stiffness, durability, and steering precision CMX Closed-Cartridge Damping — symmetrical, adjustable closed cartridges with high-flow pistons and fully tunable compression and rebound valving Tool-Free Compression Adjustment — allows quick compression changes without additional tools Hydraulic Bottom-Out Control — hydraulic bump stop helps soften hard landings while allowing maximum usable stroke 178mm Fork Spacing — provides additional clearance and flexibility for dirt and street tire setups Arctic Leopard Drop Clamp — billet aluminum drop clamp increases total fork length to 800mm Ultra-Stiff Race-Grade Axle — designed to improve steering precision, front-end feel, and stability Replaceable Brake Caliper Bracket — allows additional flexibility for future brake and wheel upgrades 220mm Brake Rotor Bracket Included — configured specifically for the Arctic Leopard XE Pro S / Enduro application Arctic Leopard Wheel Spacers Included — model-specific spacers are included for proper wheel fitment Motorcycle-Style Top Cap — allows more consistent control over steering bearing tension Arctic Leopard Compatibility This Sirris F43 CMX Fork model is designed specifically for the Arctic Leopard XE Pro S and Enduro only. The fork includes the required Arctic Leopard wheel spacers and 220mm rotor brake bracket. The fork uses a 4-bolt direct mount stem. Later XE Pro S models are equipped with a compatible direct mount stem. Some earlier XE Pro S models may require a direct mount stem upgrade, so we recommend checking your bike before installation. The Arctic Leopard XE Pro R uses a different Sirris F43 fork model because of its brake bracket configuration. Shop here for the Sirris F43 CMX Fork: Arctic Leopard XE Pro R. Complete Arctic Leopard Suspension Setup For a balanced front and rear suspension upgrade, pair the F43 CMX Fork with the Sirris R38 Rear Shock for the Arctic Leopard XE Pro S / Enduro / R. The R38 rear shock requires the matching TMB Linkage for Sirris R38 and cannot be used with the factory Arctic Leopard linkage. F43 CMX Fork Specifications Architecture Upside down fork Travel 220mm Free Length 775mm (800mm total length with drop clamp) Fork Spacing 178mm Fork Weight 4 kg per leg Stanchions 43mm high-tensile steel with hard chrome Outer Tubes Seamless 7050 aluminum, Type III hard anodized Drop Outs 6061 aluminum, Type II anodized Brake Mounting Designed for 220mm rotor; 220mm brake bracket included Triple Clamps Drop clamp, billet 6061 aluminum, Type II anodized, black Steer Tube Seamless 7050 aluminum, Type II anodized Stem Mount 4-bolt direct mount stem only Damping CMX symmetrical adjustable closed cartridge with spring-backed modified IFP Adjusters External tool-free compression; adjustable rebound Seals NOK MX seals Bushings Daido MX bushings Guards High-impact PP, 210° wraparound Fork Tuning & Rider Weight Sirris offers two spring configurations based on rider weight. Listed rider weights are body weight without riding gear; approximately 15 lbs of riding gear is factored into the recommended ranges. The weight of major upgrades such as batteries and controllers should also be considered when selecting a spring rate. Medium: 140-180 lbs — 4.0/3.6 fork springs Heavy: 180-220 lbs — 4.0/4.0 fork springs Riders near the upper end of a weight range or aggressive riders may benefit from moving to the heavier spring configuration and adjusting preload to achieve proper sag. FORK Recommendations Medium Heavy Rider Weight (lbs) (No Gear) 140-180 180-220 Spring Rate (N/mm) 4.0/3.6 4.0/4.0 Fork Height in Upper Clamp (mm) 5 5 Compression Setting 16 14 Rebound Setting 16 14 Preload Setting (mm of preload R and L fork legs) 5/5 5/5 Oil Volume (Bath Oil) 100cc 120cc Oil Weight* (bath/cartridge) 20/5 20/5 Headset Bearing Spacer reuse stock spacer, seal, bearing Steerer Spacer 5mm thick above top clamp / beneath top cap 430-38-018 x2 Caliper Bracket Caliper bracket is 220mm only. Comes stock with a 220mm rotor. 430-22-038, 90mm Wheel Spacers 430-22-036-360-02 (brake side) 430-22-036-267-02 (non-brake side) R38 Shock Settings Medium Heavy Compression Setting LSC 13 / HSC 12 LSC 11 /HSC 12 Rebound Setting 8 7 Spring Rate (N/mm, lb/in) 110 120 Preload Setting (mm) 3 3 Settings Settings are number of clicks from the closed position (full clockwise). Once they are in the closed position, back them out (counter-clockwise) according to the number of clicks indicated in the chart above to get you to factory settings. CMX Tune Starting Point: Assuming neutral riding position, and 15 lbs gear Weights of upgrades (battery, controller, etc) to be added to rider weight Riders close to a weight cut off need to adjust preload to compensate Very aggressive/pro riders to consider +1 weight class and drop preload to get sag. Especially if in the upper range. Rider preference and riding conditions may require a different setup Example: 160 lb rider without riding gear, 20 additional lbs with upgraded controller/battery Weight calculation 160+20=180 Aggressive rider = Heavy tune with low preload Relaxed rider = Medium tune with high preload Sirris F43 CMX Fork Installation Easy Direct Mount Setup Upgrade your stock Arctic Leopard XE Pro S / Enduro easily with the F43 direct mount front suspension system. No additional modifications or parts are required. 5-Hour Break-In Period Recommendation The Sirris F43 CMX Fork will break-in during the first 5 hours of use with significant improvements in friction. We recommend that you don’t make significant changes to clicker positions or valving until after the 5-hour break-in period. Owner’s Guide: Sirris F43 & R38 CMX For Arctic Leopard (PDF) ›