Target Audience:
Owners of 1987-1988 Polaris Indy 400 SKS snowmobiles seeking to perform maintenance, repairs, or diagnostics themselves.
Manual Value Proposition:
Provides essential technical data and procedural guidance that may be difficult to find elsewhere for this specific vintage model, enabling cost savings on repairs.
Comprehensive Coverage:
Hundreds of pages covering all aspects of the snowmobile, from routine maintenance to in-depth repairs.
Instant Download:
Immediate access to the manual upon purchase, facilitating prompt work.
Engine Service:
Detailed procedures for engine repair, disassembly, assembly, and troubleshooting.
Fuel System:
Carburetor adjustment, cleaning, fuel pump, fuel lines, and tank maintenance.
Ignition System:
Spark plug specifications, ignition timing, coil testing, and CDI unit diagnostics.
Lubrication System:
Oil change procedures, oil pump maintenance, and lubrication points.
Cooling System:
Radiator, fan, thermostat, coolant specifications, and flush procedures.
Drive System:
Clutch operation, belt inspection and replacement, chain case maintenance, and gear lubrication.
Suspension System:
Front and rear suspension inspection, shock absorber service, and ski alignment.
Braking System:
Brake caliper service, pad replacement, fluid flush, and linkage adjustment.
Electrical System:
Wiring diagrams, lighting system repair, battery maintenance, and switch testing.
Bodywork And Chassis:
Body panel removal, seat maintenance, track inspection, and chassis lubrication.
Routine Maintenance:
Oil changes, spark plug replacement, air filter cleaning/replacement, track tensioning, lubrication points.
Troubleshooting:
Diagnostic procedures for common and uncommon issues, fault finding guides.
Engine Repair:
Top-end rebuild, bottom-end overhaul, piston and ring replacement, gasket renewal.
Transmission Service:
Clutch adjustment, belt replacement, gear case service.
Suspension Overhaul:
Shock absorber rebuilding, spring replacement, linkage servicing.
Brake System Repair:
Brake pad and rotor replacement, hydraulic system bleeding.
Electrical Diagnostics:
Wiring harness repair, component testing (coils, switches, lighting).
Depth Of Information:
Comprehensive coverage from basic maintenance to complete engine and component overhauls, suitable for DIY enthusiasts and professional technicians.
Diagnostic Capabilities:
Detailed troubleshooting flowcharts and symptom-based diagnostics.
Rebuild Procedures:
Step-by-step instructions for major component rebuilds.
Engine Type:
2-Stroke, Twin-Cylinder
Displacement:
Approximately 398cc (actual displacement for Indy 400 models can vary slightly by year/variant, but 400 is the designation).
Bore X Stroke:
Typically around 63.0 mm x 64.0 mm for this engine family.
Cooling Method:
Fan-Cooled
Horsepower:
Estimated 40-50 HP (exact figures vary by tuning and specific model configuration).
Torque:
Torque figures are typically not prominently advertised for these models but are inherent to the engine's power curve.
Carburetion:
Dual Carburetors (e.g., Mikuni VM series, likely 30-34mm)
Fuel Type:
Unleaded Gasoline (typically 87-89 octane)
Fuel Mixture:
Pre-mix (gasoline and oil mixed before fueling) or Oil Injection System (details would be in the manual).
Ignition Type:
CDI (Capacitor Discharge Ignition)
Track Length:
SKS models typically featured longer tracks for better flotation, likely around 121-136 inches.
Ski Stance:
Standard for the era, adjustable to some extent.
Dry Weight:
Estimated 400-450 lbs (dry weight, varies based on exact configuration).
Payload Capacity:
Designed for single rider, with limited cargo capacity.
Crash Safety:
Snowmobiles of this era did not have formal crash ratings like automobiles.
Throttle Control:
Handlebar throttle lever.
Braking System:
Mechanical disc brake on the driveshaft/transmission output.
Kill Switch:
Engine kill switch located on the handlebars.
Lighting:
Headlight, taillight, and brake light (if equipped).
Oil Change Interval:
Recommended every 50-100 operating hours or annually. Specific guidance in manual.
Spark Plug Replacement:
Every 100-150 operating hours or as needed based on inspection. Consult manual for specific plug type and gap.
Clutch Belt Inspection:
Inspect for wear and cracks every 50 operating hours; replace as needed or at 100-150 hours.
Track Tensioning:
Check and adjust track tension every 50 operating hours.
Engine Oil Type:
2-Stroke oil (specific grades like API-TC or JASO FD rated, or Polaris branded oil recommended. Pre-mix ratio will be specified).
Gearcase Oil:
Specific gear oil (e.g., SAE 80W-90 GL-4 or GL-5) for the chaincase. Capacity will be specified.
Coolant Type:
Ethylene Glycol based antifreeze, typically a 50/50 mix with distilled water for fan-cooled engines, though some may just use water for lubrication of internal parts or rely on engine heat dissipation without significant coolant circulation. Manual to confirm.
Carburetor Clogging:
Common in older sleds due to stale fuel; requires cleaning and proper jetting.
Clutch Wear:
Drive and driven clutch buttons, rollers, and springs can wear over time, affecting performance.
Track Lug Damage:
Aggressive riding or improper tension can cause track damage.
Suspension Bushings:
Rubber bushings in suspension components can degrade and require replacement.
Polaris Legacy:
Polaris Industries is a long-standing American manufacturer of powersports vehicles, including snowmobiles, founded in 1954. Known for innovation and performance.
Indy Lineage:
The Polaris Indy line was a cornerstone of their snowmobile offerings, representing reliable and capable trail machines. The 'SKS' designation typically indicated a model built for 'Ski-Doo,' implying a focus on trail touring or potentially a competitor-specific adaptation or feature set.
1980S Innovation:
The 1980s saw significant advancements in snowmobile technology, including improved engine performance, suspension, and rider comfort, which the Indy 400 SKS would have benefited from.
Manufacturing Era:
Produced during a period of strong growth and competition in the snowmobile market.
