The Polaris Sportsman 400 HO is a versatile All-Terrain Vehicle (ATV) produced from 2008 to 2010, designed for both recreational pursuits and light utility tasks. Known for its robust 400cc liquid-cooled engine and capable handling, this model features independent front suspension and an automatic all-wheel-drive system for enhanced traction. With practical utility features like front and rear racks and a significant towing capacity, the Sportsman 400 HO has been recognized for its balanced performance, rider comfort, and value within its market segment, competing effectively against other mid-size ATVs of its era. This comprehensive service repair manual provides detailed guidance for the maintenance and repair of the Polaris Sportsman 400 HO models. It covers essential areas including engine overhaul, fuel system servicing, transmission and drivetrain maintenance, braking system repairs, electrical system diagnostics, and suspension and steering adjustments. The manual offers step-by-step instructions for scheduled maintenance, troubleshooting common issues, and complete system overhauls, making it an indispensable resource for owners and technicians seeking to ensure the optimal performance and longevity of their vehicle. 🏷️ Basic Information Identification Make: Polaris Model: Sportsman 400 HO Model Variant: 400 HO Years Covered: 2008, 2009, 2010 Vehicle Type: All-Terrain Vehicle (ATV) Codes Manual Product Code: Likely internal to seller, not specified in product info 👋 Introduction Market Position Market Segment: Mid-size utility ATV, known for its versatility in recreational and light work applications. Competitive Analysis Competitors: Competed against models like Yamaha Grizzly 400, Suzuki King Quad 400, and Can-Am Outlander 400 of the same era. Key Features Powertrain: Robust 400cc liquid-cooled engine, reliable AWD system. Handling: Independent front suspension, MacPherson strut front suspension, often praised for comfortable ride and capability. Utility: Front and rear racks for cargo carrying, towing capacity. 📋 Manual Details Coverage Areas General Coverage: Comprehensive service and repair for the Polaris Sportsman 400 HO models from 2008-2010. Page Count Estimated Page Count: Estimated 500+ pages (typical for a full service manual of this era) Manual Type Manual Type: Full Service Repair Manual Language Language: English Format Format: Likely PDF, potentially available in print 📖 Manual Coverage Systems Covered Engine: Engine overhaul, cylinder head, piston, crankshaft, camshaft, valve timing, lubrication system, cooling system. Fuel System: Fuel injection system (EFI), fuel pump, injectors, throttle body, fuel lines, fuel tank. Transmission Drivetrain: CVT (Continuously Variable Transmission) system, drive clutch, driven clutch, belt replacement, gearcase, differential, driveshafts, AWD system operation and service. Braking System: Hydraulic brake system, brake calipers, brake pads, brake discs, master cylinder, brake lines, parking brake. Electrical System: Battery, charging system (stator, rectifier/regulator), starter motor, ignition system, lighting, wiring diagrams, fuse box, sensors (TPS, MAP, etc.), ECU. Suspension Steering: Front and rear suspension components, shock absorbers, A-arms, ball joints, tie rods, steering column, steering rack, wheel alignment. Bodywork Chassis: Frame, plastic body panels, racks, seat, fenders, handlebars, footrests. Procedures Included Maintenance: Scheduled maintenance, oil changes, filter replacements, spark plug service, lubrication points, fluid checks and changes. Troubleshooting: Diagnostic procedures for common and uncommon issues, symptom-based troubleshooting guides, error code interpretation. Repair: Step-by-step repair instructions for all major components and systems, including disassembly, inspection, repair, and reassembly. Overhaul: Complete engine and transmission overhaul procedures, including specifications and tolerances. Diagnostics: Diagnostic testing for electrical and mechanical systems, including specific testing procedures and expected results. Technical Depth Depth: Comprehensive, from basic maintenance tasks to complete engine and driveline rebuilds. Suitable for professional mechanics and experienced DIY enthusiasts. 📊 Manual Specifications File Format File Format: PDF (typically searchable, with high-resolution diagrams) Print Quality Print Quality: High-resolution, clear diagrams and text (assuming a quality reproduction) Binding Type Binding Type: If printed: Coil-bound or perfect-bound for lay-flat usability. Paper Type Paper Type: If printed: Heavy-duty, coated paper to withstand shop conditions. ⚙️ Engine Specifications Primary Engine Engine Type: 4-stroke, SOHC, 4-valve, liquid-cooled Displacement: 375cc to 400cc (Polaris often rounded up or used variations within this range for the '400 HO' designation). Bore X Stroke: Typical for this displacement range, likely around 90mm x 62mm. Compression Ratio: Likely around 10.0:1 to 11.0:1. Power Output: Estimated 28-32 HP (horsepower) at peak RPM. Torque Output: Estimated 25-28 lb-ft (foot-pounds) at peak RPM. Performance Top Speed: Governed by CVT and gearing, typically around 45-55 mph. Fuel System Fuel Delivery: Electronic Fuel Injection (EFI) Fuel Type: Unleaded gasoline, minimum 87 octane Ignition System Ignition Type: Electronic ignition with CDI (Capacitor Discharge Ignition) or similar. Cooling System Cooling Method: Liquid-cooled Coolant Type: Ethylene glycol-based antifreeze (e.g., Polaris P/N 2870553 or equivalent, typically a 50/50 mix with distilled water). Lubrication System Oil Type: Polaris PS-4 Full Synthetic 4-Stroke Engine Oil (e.g., SAE 5W-50, P/N 2877899) or equivalent API SG, SJ, SL rated oil. Oil Capacity: Approximately 2.2 quarts (2.1 liters) with filter change. 🔧 Transmission Standard Transmission Type: Automatic, Polaris Variable Transmission (PVT) with All-Wheel Drive (AWD) engagement. Gear Selection: High, Low, Neutral, Reverse, Park. Features Clutch...