1987 Polaris Indy 400 Manual

The 1987 Polaris Indy 400 is a high-performance snowmobile featuring a 398cc liquid-cooled twin-cylinder engine, independent front suspension, and Polaris Variable Ratio (PVR) rear suspension. This manual covers safety guidelines, technical specifications, maintenance procedures, operation instructions, troubleshooting, and storage recommendations for optimal performance and longevity.

1. Features at a Glance 2. Safety Precautions 3. Specifications 4. Controls and Operation 5. Maintenance Schedule 6. Engine System 7. Fuel System 8. Electrical System 9. Suspension and Track 10. Storage Procedures 11. Troubleshooting

Features at a Glance

Key components: 398cc liquid-cooled engine, PVR rear suspension, independent front suspension, slide rail suspension system, and comprehensive instrumentation.

Feature	Description
Engine	398cc liquid-cooled twin-cylinder two-stroke
Front Suspension	Independent trailing arm with coil springs
Rear Suspension	Polaris Variable Ratio (PVR) slide rail
Track	15-inch wide rubber track with molded-in lugs
Brake System	Hydraulic disc brake
Ignition	CDI electronic ignition
Fuel Capacity	11.5 gallons
Oil Injection	Automatic oil injection system
Starting System	Electric start with backup recoil
Instrumentation	Speedometer, tachometer, fuel gauge, warning lights

Safety Precautions

Always follow safety guidelines to prevent accidents and injuries.

Wear appropriate safety gear: helmet, goggles, gloves, and insulated clothing.
Never operate under the influence of alcohol or drugs.
Inspect snowmobile before each use for proper operation.
Operate only in designated areas and obey all local regulations.

WARNING! Snowmobile operation requires skill and attention. Always maintain control and be aware of terrain conditions.

Specifications

Engine Type: 398cc liquid-cooled twin-cylinder two-stroke
Bore x Stroke: 68mm x 55mm
Carburetion: Twin VM34 Mikuni carburetors
Ignition: CDI electronic ignition
Starting System: Electric start with auxiliary recoil
Fuel Capacity: 11.5 gallons (43.5 liters)
Oil Capacity: 3.2 quarts (3.0 liters)
Track Length: 121 inches
Track Width: 15 inches
Dry Weight: 475 pounds (215 kg)
Brake Type: Hydraulic disc

Controls and Operation

Familiarize yourself with all controls before operation.

Main Controls: Throttle lever, brake lever, choke, ignition switch, emergency stop switch, reverse lever (if equipped).

Operation: Start engine using electric start or recoil backup. Allow engine to warm up before operation. Use throttle progressively and brake smoothly. Monitor instruments for proper operation indicators.

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Interval	Maintenance Items
Before each use	Check fuel level, oil level, track condition, brake operation
Every 500 miles	Change engine oil, inspect drive belt, check suspension
Every 1,000 miles	Replace spark plugs, clean air filter, inspect track tension
Every 2,000 miles	Replace drive belt, inspect carburetors, check clutch operation
Seasonal	Full inspection, lubrication, storage preparation

Engine System

398cc liquid-cooled twin-cylinder two-stroke engine maintenance procedures.

Spark Plugs: Replace every 1,000 miles or as needed. Gap: 0.020-0.024 inches.
Cooling System: Check coolant level regularly. Maintain 50/50 coolant mixture.
Compression Test: Should read 120-150 PSI per cylinder when warm.
Oil Injection: Check oil level before each ride. Use Polaris synthetic injection oil.

CAUTION! Always allow engine to cool before performing maintenance.

Fuel System

Twin VM34 Mikuni carburetors with automatic oil injection.

Fuel Type: Use 87 octane or higher unleaded gasoline.
Fuel Filter: Replace annually or every 2,000 miles.
Carburetor Adjustment: Idle speed: 1500-1700 RPM. Pilot screw: 1.5 turns out.
Fuel Lines: Inspect for cracks or leaks regularly.

WARNING! Gasoline is highly flammable. No smoking during fuel system maintenance.

Electrical System

12-volt DC system with CDI ignition and comprehensive instrumentation.

Battery: 12V 18Ah maintenance-free
Charging System: AC magneto with rectifier/regulator
Headlights: Dual 55W halogen
Tail Light: 5W incandescent
Fuses: Main 20A, Accessory 10A

Check battery terminals for corrosion and ensure proper charging voltage (13.5-14.5V at 3000 RPM).

Suspension and Track

Independent front suspension and PVR rear suspension maintenance.

Track Tension: Adjust to 1-1.5 inches of sag between rear idlers.
Suspension Springs: Check for sagging or damage.
Slide Rails: Inspect for wear and lubricate with graphite.
Front A-arms: Check bushings and ball joints for wear.

Tip: Proper track tension improves performance and extends component life.

Storage Procedures

Proper storage prevents damage during off-season periods.

Fuel System: Add fuel stabilizer and run engine for 5 minutes.
Battery: Remove and store fully charged in cool, dry location.
Track: Lift off ground to prevent flat spots.
Cleaning: Wash thoroughly and apply protectant to plastic components.

CAUTION! Store in dry location away from direct sunlight and moisture.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel, spark, compression	Check fuel level, spark plugs, compression; verify choke operation
Poor performance	Clutch, carburetion, exhaust	Inspect drive clutch, clean carburetors, check exhaust system
Electrical failure	Battery, fuses, connections	Test battery voltage, check fuses, inspect wiring connections
Overheating	Coolant, water pump, thermostat	Check coolant level, inspect water pump, test thermostat
Track issues	Tension, alignment, wear	Adjust track tension, check alignment, inspect for damage

Service: Contact authorized Polaris dealer for complex repairs.

Parts: Use genuine Polaris parts for optimal performance and warranty coverage.