Market Segment:
Entry-level to mid-range trail and utility snowmobile for the 1988 model year.
Competitors:
Competed with models from Ski-Doo (e.g., Formula series), Arctic Cat (e.g., Prowler), and Yamaha (e.g., Phazer).
Key Features:
Reliable 400cc engine, balanced chassis for trail riding, SKS designation suggests a slightly longer track or utility focus over the standard Indy 400.
Engine:
Detailed troubleshooting, repair, and maintenance of the 400cc engine.
Fuel System:
Carburetor adjustment, cleaning, and rebuild; fuel pump and lines.
Ignition System:
Ignition timing, spark plugs, CDI unit, magneto inspection and testing.
Drive System:
Clutch (primary and secondary) inspection, adjustment, and replacement; chaincase maintenance and lubrication.
Suspension:
Front and rear suspension system inspection, lubrication, and component replacement (shocks, springs, arms).
Braking System:
Brake caliper, master cylinder, brake lines, and brake pad maintenance and repair.
Electrical System:
Wiring diagrams, lighting system, starter system, battery maintenance, and troubleshooting.
Cooling System:
If applicable (e.g., fan-cooled), radiator/heatsink cleaning and fan operation.
Track And Skis:
Track tension adjustment, inspection for wear, ski alignment, and ski rubber maintenance.
Maintenance:
Scheduled maintenance, lubrication points, and routine inspections.
Troubleshooting:
Diagnostic guides for common problems and systematic fault finding.
Repair:
Step-by-step instructions for component disassembly, repair, and reassembly.
Overhaul:
Engine and major component overhaul procedures.
Adjustments:
Carburetor, clutch, chain tension, and brake adjustments.
Specifications:
Torque values, clearances, fluid capacities, and performance data.
Depth:
Comprehensive, covering detailed internal engine work, clutch recalibration, and electrical system diagnostics.
File Format:
PDF (assumed for digital sales); print format is physical paper.
Print Quality:
Varies by source; original print quality would be typical for factory manuals. Digital scans may have variable clarity.
Binding Type:
Original: Staple-bound or perfect bound. Digital: N/A.
Paper Type:
Original: Standard newsprint or matte paper. Digital: N/A.
Engine Manufacturer:
Polaris
Engine Type:
2-stroke, piston port induction
Engine Displacement:
Approximately 398cc (often rounded to 400cc)
Engine Configuration:
Vertical twin-cylinder
Cooling Method:
Fan-cooled
Horsepower:
Estimated 35-45 HP (typical for this class and era)
Torque:
Not typically published for this class, but optimized for low-end and mid-range power.
Carburetor Type:
Likely a dual Mikuni VM or Keihin carburetors (e.g., 30-34mm).
Fuel Type:
Unleaded gasoline (minimum 87 octane recommended)
Oil Injection:
Yes, automatic oil injection system.
Transmission Type:
CVT (Continuously Variable Transmission) - Polaris P-85 Primary and P-90 Secondary clutch system.
Optional Transmission:
N/A for this model; CVT was standard.
Drive Mechanism:
Chain drive to track.
Gear Ratios:
CVT system provides continuously variable ratios, no fixed gear ratios.
Clutch Maintenance:
Requires periodic cleaning, inspection, and belt replacement.
Overall Length:
Approx. 105-110 inches (typical for this class, SKS may be slightly longer).
Overall Width:
Approx. 46-48 inches.
Dry Weight:
Approx. 400-430 lbs (dry weight).
Track Width:
Standard 15-inch track width.
Track Length:
Likely 121 inches or 133 inches, SKS variant often featured a longer track.
Safety Ratings:
No formal crash test ratings like automobiles. Safety focused on operational controls and stability.
Braking System:
Hydraulic disc brake, typically on the driveshaft.
Throttle Control:
Thumb throttle with safety detent.
Kill Switch:
Engine kill switch, often with a lanyard attachment point.
Headlight:
Standard headlight for visibility.
Taillight:
Standard taillight/brake light.
Windscreen:
Provides rider protection from wind and snow.
Clutch Service:
Inspect clutches every 500 miles or annually; clean and check belt condition.
Engine Tune Up:
Check spark plugs and ignition system annually; carburetor synchronization and cleaning as needed.
Lubrication:
Lubricate suspension, steering components, and chaincase at the beginning of each season and as specified in the manual.
Track Tension:
Check and adjust track tension regularly, especially after initial break-in or heavy use.
Chaincase Oil:
Polaris recommends specific chaincase lubricant or equivalent API GL-4 gear oil.
2 Stroke Oil:
Use a high-quality, low-ash, synthetic 2-stroke snowmobile oil (e.g., Polaris VS-2, Amsoil Dominator, or equivalent).
Brake Fluid:
DOT 3 or DOT 4 hydraulic brake fluid.
Clutch Wear:
Common for clutches to require service or belt replacement due to heat and wear.
Carburetor Fouling:
Carburetors can be prone to gumming up if fuel is left sitting for extended periods.
Recoil Starter:
Recoil starter mechanism can sometimes fail or become stiff.
Suspension Bushings:
Wear in suspension bushings can lead to imprecise handling.
Brand Origin:
Polaris Industries was founded in 1954 in Roseau, Minnesota, USA.
Brand Specialization:
Polaris is a long-standing and prominent manufacturer of snowmobiles, ATVs, and other powersports vehicles.
Indy Lineage:
The Indy nameplate has been a staple for Polaris, signifying popular trail-oriented snowmobiles. The 400cc engine was a common and reliable powerplant for this class.
Sks Designation:
The SKS (often standing for 'Special) typically indicated a slightly more rugged or versatile package, often with a longer track for better flotation or traction.
Production Period:
The 1988 model year represents a specific iteration of the Indy 400 SKS, building upon previous designs and technology of the era.
Historical Accolades:
Polaris snowmobiles of this era were generally well-regarded for their reliability and performance within their market segments. Specific awards for the 1988 Indy 400 SKS are not readily documented.
Consumer Satisfaction:
Based on industry reviews and owner feedback from the period, Polaris Indy models were considered strong contenders.
Industry Certifications:
N/A for snowmobiles in the traditional sense of automotive certifications.
