1987 Polaris Trail Boss 250 Manual Download

The 1987 Polaris Trail Boss 250 is a rugged ATV featuring a 244cc two-stroke engine, automatic Polaris Variable Transmission (PVT), front and rear suspension, hydraulic drum brakes, and durable steel frame. This manual covers safety guidelines, specifications, maintenance procedures, troubleshooting, and operational instructions for optimal performance and longevity.

1. Features at a Glance 2. Safety Information 3. Specifications 4. Maintenance Schedule 5. Controls and Operation 6. Engine Maintenance 7. Transmission System 8. Electrical System 9. Brake System 10. Troubleshooting 11. Parts and Accessories

Features at a Glance

Key components: 244cc two-stroke engine, Polaris Variable Transmission, front and rear suspension, hydraulic drum brakes, steel frame.

Feature	Description
Engine Type	244cc two-stroke, air-cooled
Transmission	Polaris Variable Transmission (PVT)
Drive System	2WD with shaft drive
Brakes	Hydraulic drum brakes front and rear
Suspension	Front: Independent A-arm; Rear: Swingarm
Fuel Capacity	3.5 gallons
Dry Weight	Approximately 350 lbs
Tires	Front: 22x7-10; Rear: 22x11-10
Load Capacity	300 lbs including rider
Starting System	Electric start with backup pull start

Safety Information

Always wear appropriate safety gear and follow operating guidelines.

Wear helmet, eye protection, gloves, and protective clothing.
Inspect ATV before each use for damage or loose parts.
Operate only in approved areas and avoid public roads.
Do not carry passengers; this is a single-rider vehicle.
Keep hands and feet away from moving parts during operation.

WARNING! Never operate under the influence of alcohol or drugs. Always follow local regulations.

Specifications

Engine: 244cc two-stroke, air-cooled
Bore x Stroke: 70mm x 64mm
Compression Ratio: 6.5:1
Fuel System: Mikuni VM34SS carburetor
Ignition System: CDI electronic ignition
Transmission: Polaris Variable Transmission (PVT)
Final Drive: Shaft drive
Suspension Travel: Front: 5.5 inches; Rear: 5.0 inches
Ground Clearance: 6.5 inches
Overall Dimensions: 74" L x 42" W x 42" H

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Service Interval	Maintenance Items
Before each ride	Check tire pressure, brakes, controls, lights
20 hours/100 miles	Change engine oil, check drive chain tension
50 hours/250 miles	Clean air filter, inspect spark plug
100 hours/500 miles	Change transmission fluid, inspect brakes
Annual	Full inspection, lubricate all fittings

Controls and Operation

Familiarize yourself with all controls before operation.

Main Controls: Throttle lever, brake lever, ignition switch, choke, gear selector, light switch.

Starting Procedure: Turn fuel valve on, set choke for cold starts, turn ignition key, press start button or use pull start. Allow engine to warm up before riding.

Operating Tips: Use smooth throttle inputs, avoid sudden braking, maintain proper tire pressure, and regularly check fluid levels.

Engine Maintenance

Proper engine care ensures reliable performance.

Oil Change: Drain old oil, replace filter, refill with recommended 2-stroke oil.
Air Filter: Clean foam filter with solvent, re-oil with filter oil.
Spark Plug: Check gap (0.025 inches), replace if worn or fouled.
Carburetor: Clean jets and passages, adjust idle mixture as needed.
Cooling System: Keep cooling fins clean and free of debris.

CAUTION! Allow engine to cool before performing maintenance.

Transmission System

The Polaris Variable Transmission requires regular maintenance.

Belt Inspection: Check for wear, cracks, or glazing every 50 hours.
Belt Replacement: Follow service manual procedure for proper installation.
Drive Clutch: Inspect rollers and weights for wear.
Driven Clutch: Check spring tension and sheave wear.
Lubrication: Grease fittings every 100 hours or as needed.

Tip: Always use genuine Polaris replacement parts for optimal performance.

Electrical System

Maintain proper electrical system function.

Component	Specification	Maintenance
Battery	12V, 18Ah	Check terminals, maintain charge
Stator	AC output	Test resistance per manual
CDI Unit	Electronic ignition	Keep connections clean and dry
Lights	Headlight, taillight	Check bulbs and wiring
Fuses	15A main fuse	Carry spare fuses

Brake System

Hydraulic drum brakes require regular inspection and maintenance.

Brake Fluid: Check level in master cylinder, use DOT 3 or 4 fluid.
Brake Pads: Inspect for wear, replace if thickness below 1/8 inch.
Brake Adjustment: Adjust cable tension as needed for proper lever feel.
Bleeding: Bleed system if spongy feel or air in lines.
Drum Inspection: Check for scoring or excessive wear.

WARNING! Test brakes in safe area before each ride.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel, spark, compression	Check fuel flow, spark plug, compression
Poor performance	Clogged filter, carb issues	Clean air filter, adjust carburetor
Transmission slipping	Worn belt, clutch issues	Inspect belt, check clutch operation
Electrical failure	Battery, connections	Test battery, check all connections
Brake problems	Fluid, pads, adjustment	Check fluid level, pad wear, adjust cables

Service: Contact authorized Polaris dealer for complex issues.

Parts and Accessories

Genuine Polaris parts ensure proper fit and performance.

Engine parts: Pistons, rings, gaskets, bearings
Transmission: Belts, clutch components, seals
Brake components: Pads, shoes, cables, fluid
Electrical: Bulbs, switches, wiring harness
Accessories: Winch kits, racks, cargo carriers

Always use parts meeting original equipment specifications.