1981 John Deere SPORTFIRE 440 Snowmobile Service & Repair Manual (P/N TM-1222)

John Deere technical manual P/N TM-1222, December 1981 edition, covers service and repair of the 1980–1982 SPORTFIRE 440, including the J44SJ, J44SK, and J44SL identification codes.

• Engine repair: Engine removal, crankcase disassembly, crankshaft and piston inspection, outer bearing replacement, compression testing, and crankcase pressure testing.

• Carburetor and lubrication: Mikuni carburetor overhaul, altitude and temperature jetting charts, fuel delivery checks, and oil injection pump testing and synchronization.

• Cooling and recoil starter: Fan belt adjustment, fan and bearing replacement, recoil starter disassembly, and starter spring winding.

• Electrical diagnosis: CDI fault isolation, ignition timing, lighting and voltage regulator tests, wiring diagrams, and optional electric start kit repair.

• Power train and brakes: Drive and driven sheave service, belt alignment, chain case and shaft repairs, and mechanical disk brake adjustment.

• Suspension and steering: Separate serial-specific suspension and rubber track sections, wear component replacement, ski alignment, and steering linkage repair.

This manual suits technicians and experienced owners familiar with two-stroke engine service and equipped for bearing work, clutch alignment, and specialized ignition testing.

TA440B Engine, Cooling Fan, and Recoil Starter

The FIREBURST TA440B piston-ported engine section covers intake manifold and muffler removal, crankshaft runout checks, piston ring gap inspection, and reassembly. Compression diagnosis and the JDM-44 crankcase pressure test help distinguish sealing problems from fuel or ignition faults.

Internal repair limits: Outer crankshaft bearings can be replaced; damaged inner bearings require crankshaft assembly replacement. The chrome-plated cylinders require replacement when outside specification and are not intended for honing or reboring.

Cooling-system procedures cover fan belt tension and fan bearing replacement. Recoil starter instructions include spring handling and rewinding with the JDM-113 Starter Spring Winding Tool.

Mikuni Carburetor and Oil Injection Variants

The Mikuni VM34/231 chapter covers float chamber settings, choke and throttle cable adjustment, idle circuits, and the high-speed power jet system. Carburetor cutaways explain fuel flow, while the altitude and temperature chart identifies the corresponding jetting and idle-speed specifications.

Lubrication change: Serial numbers 120,001–190,000 use premixed fuel; oil injection procedures apply from 190,001. Pump output testing and control cable synchronization are covered for the later configuration. The fuel pump section provides flow checks, diaphragm inspection, cleaning, and replacement criteria.

CDI Tests, Lighting, and Optional Electric Start

Ignition coil, CDI unit, exciter coil, and pulser coil tests use the JDM-74 tester and JDM-74A-6 harness. These component tests help isolate the source of a weak or missing spark. The CDI test section warns that a 12-volt test light can destroy the system.

The Electrical System and Electric Start Kit diagrams show wiring and switch connections. Alternator and voltage regulator testing, ignition timing, the Battery Test Procedure chart, and the battery voltage chart support electrical diagnosis. Starter motor and drive repair, solenoid and rectifier checks, and a 12-volt light bulb chart are also included.

Sheaves, Belt Alignment, and Chain Case Repairs

The John Deere (Comet) 102C drive sheave and John Deere driven sheave chapters cover bushings, rollers, guide buttons, spring installation, and reassembly. Clutching recommendations distinguish elevation applications, and the Aligning Drive Belt drawing supports center-distance and offset checks with the JDM-81 tool.

Chain case coverage includes sprocket alignment, secondary shaft and drive shaft removal, bearings, and seals. Mechanical disk brake procedures cover disk and puck replacement, cable adjustment, and brake light checks.

Serial-Specific Suspension, Track, and Steering

Separate suspension and track sections distinguish serial numbers 120,001–190,000 from 190,001 onward. Exploded suspension views and wear-bar, rear idler, and spring procedures identify the differences; track repair distinguishes earlier grouser bars from later wear clips and includes track stud pattern drawings.

Ski and steering work includes wear rods, wear plates, spindle bushings, tie rods, drag links, and steering post replacement. Ski alignment drawings also distinguish machines before and after serial number 155,001. Hood, tunnel, and pan repairs are outside this manual's scope.

Support the snowmobile securely for suspended-track checks and keep clear of the rotating track and sheaves.

Examples of Engine Torque and Spark Plug Data

These examples are a small selection of the engine service data in the manual.

The TA440B torque table lists cylinder head fasteners at 22 N·m (16 ft-lb) and flywheel-to-crankshaft attachment at 81 N·m (60 ft-lb).

The electrical specifications identify a factory spark plug gap of 0.025 in. (0.635 mm), accompanied by replacement guidance rather than a regapping procedure.

PDF Search, Navigation, and Page Breakdown

Text search and diagram detail: An embedded OCR layer supports text searches, with recognition errors in some labels. Nine bookmarks cover the contents, main sections, and wiring diagram entry. Small wiring labels require zooming; parts of the optional electric-start diagram are faint.

Download one printable English PDF with 168 pages total: two opening contents/introduction pages and 166 section pages, including 19 otherwise blank pages carrying headers or footers. All are included in the total.