1988 Polaris Trail Boss 250 Manual

The 1988 Polaris Trail Boss 250 is a rugged all-terrain vehicle featuring a 244cc air-cooled 2-stroke engine, automatic Polaris Variable Transmission (PVT), front and rear suspension, front and rear hydraulic brakes, electric start with pull start backup, front and rear cargo racks, and full instrumentation. Below are key sections for safety, features, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Safety Information 3. Controls and Operation 4. Specifications 5. Maintenance Schedule 6. Fuel and Oil System 7. Electrical System 8. Brake System 9. Tire Information 10. Storage Procedures 11. Troubleshooting

Features at a Glance

Key components: 244cc 2-stroke engine, PVT transmission, front and rear suspension, hydraulic disc brakes, cargo racks.

FeatureDescription
Engine244cc air-cooled 2-stroke single cylinder
TransmissionPolaris Variable Transmission (PVT) automatic
Starting SystemElectric start with pull start backup
BrakesFront and rear hydraulic disc brakes
SuspensionFront independent A-arm, rear swingarm
Fuel Capacity3.0 gallons (11.4 liters)
Cargo CapacityFront: 50 lbs, Rear: 100 lbs
TiresFront: 21x7-10, Rear: 20x10-9
Dry Weight365 lbs (166 kg)
InstrumentationSpeedometer, odometer, fuel gauge, warning lights

Safety Information

Always wear proper safety gear and follow operating guidelines.

  1. Always wear DOT-approved helmet, eye protection, gloves, and protective clothing.
  2. Never operate under the influence of alcohol or drugs.
  3. Inspect ATV before each use for proper tire pressure, brake function, and fluid levels.
  4. Never carry passengers - designed for operator only.
  5. Avoid paved surfaces - designed for off-road use only.

WARNING! This ATV can be hazardous to operate. Always follow safety guidelines and receive proper training.

Controls and Operation

Familiarize yourself with all controls before operation.

  1. Starting: Turn key to ON, set choke if cold, press brake, press start button.
  2. Transmission: Automatic PVT - no shifting required.
  3. Brakes: Front and rear hydraulic disc brakes operated by hand levers.
  4. Throttle: Right thumb lever - push forward to accelerate.
  5. Emergency Stop: Kill switch on right handlebar.

CAUTION! Always use both brakes for maximum stopping power.

Specifications

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

ServiceEvery 25 hrsEvery 100 hrsEvery 200 hrs
Engine oil change✓
Air filter cleaning✓
Spark plug replacement✓
Brake fluid change✓
Drive chain adjustment✓
CVT belt inspection✓✓

Fuel and Oil System

Proper fuel mixture is critical for 2-stroke engine operation.

  1. Fuel: Use 87 octane or higher unleaded gasoline.
  2. Oil: Polaris Premium 2-stroke injection oil only.
  3. Mix Ratio: 40:1 (3.2 oz oil per 1 gallon gasoline).
  4. Carburetor: Mikuni VM34SS with choke and throttle cable adjustments.
  5. Fuel Filter: Replace annually or every 100 hours.

WARNING! Never use automotive motor oil - use only recommended 2-stroke oil.

Electrical System

12-volt DC system with battery and charging system.

  1. Battery: 12V 14Ah maintenance-free.
  2. Charging System: AC magneto with rectifier/regulator.
  3. Lights: Headlight, taillight, brake light.
  4. Fuses: Main 20A fuse near battery.
  5. Spark Plug: NGK BR8ES, gap 0.020-0.024 in.

Tip: Keep battery terminals clean and tight for reliable starting.

Brake System

Hydraulic disc brakes front and rear.

  1. Brake Fluid: DOT 4 hydraulic fluid.
  2. Pad Replacement: Replace when worn to 1mm thickness.
  3. Bleeding: Required when fluid appears dark or spongy feel.
  4. Rotor Thickness: Minimum 3.0mm front, 3.5mm rear.

CAUTION! Never use petroleum-based fluids in brake system.

Tire Information

Proper tire pressure and maintenance essential for handling.

Tire PositionSizePressure (psi)
Front21x7-103.5 psi
Rear20x10-93.5 psi

WARNING! Operating with incorrect tire pressure can cause loss of control.

Storage Procedures

Proper storage prevents damage during periods of non-use.

  1. Fuel System: Add fuel stabilizer and run engine for 5 minutes.
  2. Battery: Disconnect negative terminal or use battery maintainer.
  3. Tires: Inflate to maximum pressure and elevate off ground.
  4. Cleaning: Wash thoroughly and apply protectant to plastic surfaces.
  5. Cover: Use breathable cover in dry, well-ventilated area.

Troubleshooting

SymptomPossible CauseCorrective Action
Engine won't startFuel, spark, compressionCheck fuel mixture, spark plug, compression
Poor performanceClogged air filter, carburetorClean air filter, inspect carburetor jets
Electrical failureBattery, fuses, connectionsCheck battery voltage, fuses, clean connections
Brakes spongyAir in lines, worn padsBleed brake system, inspect pads
Transmission slippingWorn belt, dirty sheavesInspect CVT belt, clean sheaves

Service: Contact authorized Polaris dealer for major repairs.

Parts: Use only genuine Polaris replacement parts.

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