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Harley Transmission Serial Numbers

Harley Davidson® VIN Identification Guide

Finding out what year a Harley Davidson engine was made can be important for a number of reasons. However, decoding an engine’s vehicle identification number can be challenging and confusing. Hidden within a Harley’s engine VIN will be the year that engine was made.

This list is unofficial and is not gospel, only what I have been able to cross in various manuals, web sites and dealerships. If you have more updated info on this data, please let me know.

Thanks!!

Year Groups

1903-1909 | 1910-1919 | 1920-1929 | 1930-1936 | 1937-1961 | 1962-1969 | 1970-1980 | 1981-2000 | 2001-2009 | 2010-Present

Model Info

1920 | 1921 | 1922 | 1923 | 1924 | 1925 | 1926 | 1927 | 1928 | 1929

1920

Top

    Main Models

    • Model 20F - Solo, 61ci F-head V-twin, chain drive, magneto ignition, 8.68 HP, 60.34 c.i., number preceded by 20T, three speed
    • Model 20FS - Sidecar Twin, 61ci F-head V-twin, 3 speed, magneto, sidecar gearing.
    • Model 20J - Solo, 61ci F-head V-twin, chain drive, magneto ignition, 8.68 HP, number preceded by L20T, three speed, electrical system
    • Model 20JS - Sidecar Twin, 61ci F-head V-twin, 3 speed, electrical system, sidecar gearing
    • Model 20WF - Sport Model Solo, 35.64ci front to back horizontally opposed twin, 3 speed
    • Model 20WJ - Sport Model Solo, 35.64ci front to back horizontally opposed twin, 3 speed, electrical system

    Specialty Models

    • Model 20FA - 'A' motor F-head V-twin, 3 speed, magneto ignition
    • Model 20FB - 'B' motor F-head V-twin, 3 speed, magneto
    • Model 20FCA - '500 CA' motor F-head V-twin, 3-1/2' stroke, aluminum pistons, magneto, 3 speed.
    • Model 20FCAB - '500 CAB' motor F-head V-twin, 4' stroke, aluminum pistons, magneto, 3 speed
    • Model 20FD - 74ci F-head V-twin, 3 speed, magneto
    • Model 20FDS - 74ci F-head V-twin, 3 speed, magneto, sidecar gearing
    • Model 20FE - 'E' motor F-head V-twin, 3 speed, magneto
    • Model 20FF - '500' motor F-head V-twin, 3 speed, magneto
    • Model 20FFA - '500 A' motor f-head V-twin, 3-1/2' stroke, aluminum pistons, magneto, 3 speed
    • Model 20JA - 'A' motor F-head V-twin, 3 speed, electrical system
    • Model 20JB - 'B' motor F-head V-twin, 3 speed, electrical system
    • Model 20JD - 74ci F-head V-twin, 3 speed, electrical system
    • Model 20JDS - 74ci F-head V-twin, 3 speed, electrical system, sidecar gearing
    • Model 20JE - 'E' motor F-head V-twin, 3 speed, electrical system
    • Model 20JF - '500' motor F-head V-twin, 3 speed, electrical system

    Sidecars and Chassis

    • Model 20L - right-hand single-passenger sidecar
    • Model 20LC - right-hand single-passenger sidecar chassis
    • Model 20LR - right-hand single-passenger Roadster sidecar
    • Model 20LX - right-hand Speedster sidecar
    • Model L20L - left-hand single-passenger sidecar
    • Model L20LC - left-hand single-passenger sidecar chassis
    • Model L20LR - left-hand single-passenger Roadster Sidecar
    • Model 20M - standard commercial sidecar
    • Model 20PC - double-bar chassis
    • Model 20Q - two-passenger sidecar chassis, 56in-tread
    • Model 20QA - standard closed commercial van, 56in-tread chassis
    • Model 20QB - standard open commercial van, 56in-tread chassis
    • Model 20QL - right-hand two passenger sidecar
    • Model QC3 - 3-stake platform Parcel Car, 56in-tread chassis
    • Model QC4 - 4-stake platform Parcel Car, 56in-tread chassis
    • Model 20WD - two-compartment Parcel Car, 56in-tread chassis

    Production: 28,189

    • Model F - 7,579
    • Model J - 14,192
    • Model WF - 4,459
    • Model WJ - 810

    Options

      Dealers racing frame; open at bottom; used with FCA-motor
      Schebler Deluxe carburetor
      Acetylene lighting
      Flat front mudguard
      Rear brake, hand operated
      Mesinger Air cushion saddle
      All weather tread, Goodyear Blue Streak tires
      Firestone Non-Skid tires
      Goodrich Safety-Tread tires
      Pennsylvania Vacuum Cup black tread tires
      Speedometer
      Front stand
      Luggage carrier

    Paint Colors

      Olive Green with Pullman Coach Green broad striping edged in Pea Green pinstripes with Black center pinstripe

    Series F, and J Big Twins

    First Year

      Revised front and rear cylinders
      Inlet pushrods, from '500' motors
      Pushrod-spring covers
      Clutch dust ring
      Revised rear brake band
      Revised brake lever on drum
      Revised headlight body
      Headlight placed above horn
      Clear headlight lens
      Red tailight lens
      Generators and coils made by H-D (late year, Series J only)

    Only Year

      Revised headlight body style (early year) that was revised again midyear.

    Series W Sport Twins

    First Year

      Electric lighting offered starting midyear, with the introduction of the model WJ
      Battery case and revised tool-box cover and locks (Model WJ)
      Headlight body (Model WJ)
      Clear headlight lens (Model WJ)
      Headlight placed above horn (Model WJ)
      Generators and colis built by H-D (Model WJ)
      3-3/8in front motor-clamp-plate studs
      Front motor-clamp spacer
      Revised front footboard support
      Revised foot-clutch lever
      Revised foot-clutch-lever friction spring
      Revised clutch operating-rod-end
      Starter-crank bracket bolt
      Luggage carrier brace

    First Year

      'E' motor classification for the 'Fast Motors'
      'E' motors feature aluminum pistons and drilled connecting rods
      Revised right and left flywheels on 'E' motors
      'E' motor cylinders stamped with 'E' on left side

1921

Top

    Main Models

    • Model 21CD - Commercial: 37ci F-head single, 3 speed, magneto ignition
    • Model 21F - 61ci F-head V-twin, chain drive, 3 speed, magneto ignition, 8.68 HP, number preceded by 21F
    • Model 21FD - Solo: 74 ci F-head V-twin, chain drive, 3 speed, magneto ignition, 9.5 HP, number preceded by 21FD
    • Model 21FDS - Sidecar Twin: 74 ci F-head V-twin, chain drive, 3 speed, magneto ignition, sidecar gearing, 9.5 HP
    • Model 21FS - Sidecar Twin: 61ci F-head V-twin, 3 speed, magneto ignition, sidecar gearing
    • Model 21J - Solo: 61ci F-head V-twin, 3 speed, chain drive, generator, 8.68 HP, number preceded by 21J
    • Model 21JS - Sidecar Twin: 61ci F-head V-twin, 3 speed, electrical system, sidecar gearing
    • Model 21JD - Solo: 74ci F-head V-twin, chain drive, 3 speed, generator, 9.5 HP, number preceded by 21JD
    • Model 21JDS - Sidecar Twin: 74ci F-head V-twin, 3 speed, electrical system, sidecar gearing
    • Model 21WF - Solo: 35.64ci (584.03cc) front to back horizontally opposed twin, three speed transmission, magneto ignition
    • Model 21WJ - Solo: 35.64ci (584.03cc) front to back horizontally opposed twin, three speed transmission, electrical system

    Specialty Models

    • Model 21FA - 'A' motor 61ci F-head V-twin, 3 speed, magneto ignition
    • Model 21FDA - 'A' motor 74ci F-head V-twin, 3 speed, magneto
    • Model 21FCA - 'T' motor F-head V-twin, magneto ingition, 3 speed.
    • Model 21FE - 'E' motor F-head V-twin, 3 speed, magneto
    • Model 21JA - 'A' motor F-head V-twin, 3 speed, electrical system
    • Model 21JDA - 'A' motor 74ci F-head V-twin, 3 speed, electrical system
    • Model 21JE - 'E' motor F-head V-twin, 3 speed, magneto ignition

    Sidecars and Chassis

    • Model 21L - right-hand single-passenger sidecar
    • Model 21LC - right-hand single-passenger sidecar chassis
    • Model 21LR - right-hand single-passenger Roadster sidecar
    • Model 21LX - right-hand Speedster sidecar
    • Model L21L - left-hand single-passenger sidecar
    • Model L21LR - left-hand single-passenger Roadster Sidecar
    • Model 21M - standard commercial sidecar
    • Model 21Q - two-passenger sidecar chassis, 56in-tread
    • Model 21QA - standard closed commercial van, 56in-tread chassis
    • Model 21QB - standard open commercial van, 56in-tread chassis
    • Model 21QD - two-compartment Parcel Car, 56in-tread chassis
    • Model 21QL - right-hand two-passenger sidecar

    Production: 10,202

    • Model F - 2,413
    • Model FD - 277
    • Model J - 4,526
    • Model JD - 2,321
    • Model - WF - 1,100
    • Model WJ - 823

    Options

      Schebler Deluxe carburetor
      Flat front mudguard
      Hand brake (Sport Model)
      Heel brake (Big Twins)
      Front stand
      Luggage carrier
      Ammeter,complete
      Speedometer by Corbin Brown
      Speedometer by Johns-Manville
      Firestone Non-Skid tires
      All-weather tread Goodyear Blue Streak tires
      Goodrich Safety-Tread tires

    Paint Colors

      Olive Green with Pullman Coach Green broad striping edged in Pea Green pinstripes with Black center pinstripe

    Series CD Big Singles

    First Year

      The CD is a new Big Single model for commercial use
      Engine: 37ci single made by removing one cylinder from the 74ci Big Twin motor
      Chassis: standard chassis used on the V-Twin models

    Only Year

      Olive painted crankcases
      Spoked flywheels

    Series F and J 61ci Big Twins

    First Year

      Solid flywheels (late year)
      Revised connecting rods, pistons, piston pins, and piston rings
      Front stand
      One-piece tubular steel handlebars
      New front and rear fenders with center rib and side panels on front fender
      Concave section on front fender for forks
      Revised tanks
      Revised tool-box cover (electric modles)
      Revised rear hub shell
      Revised front footboard support rod

    Only Year

      No compression plates (solo models)

    Series FD and JD 74ci Big Twins

    First Year

      The series FD and JD F-head Big Twins are new models created by boring and stroking the engine used in the Series F and J Big Twins
      Engine: 74.66ci F-head V-twin with 3-7/16x4in bore and stroke and output of 18hp
      1-1/4in Schebler carburetor
      Silichrome-alloy exhaust valves
      New right and left crankcases
      New cylinders and heads
      Solid flywheels
      Front and read exhaust pipes

    Only Year

      Olive-painted crankcases
      Coach Green broad stripe down middle of front fender

    Series W Sport Twins

    First Year

      Big Twin-style tank trim
      Fenders both center ribbed
      Side panels on front fender
      Brake-lever guide
      Revised headlight body

    Specialty Notes

      The 'A' V-Twin motor is now a special high-speed motor for police use
      The 'B' V-Twin motor is now a special high-compression motor for high altitudes
      Te 'E' V-Twin motor is now a special racing motor.

1922

Top

    Main Models

    • Model 22CD - Commercial: 37ci F-head single, 3 speed
    • Model 22F - Solo: 61ci F-head V-twin, chain drive, magneto ignition, 8.68 HP, number preceded by 22F, three speed
    • Model 22FD - 74ci F-head V-twin, chain drive, magneto ignition, 9.5 HP, number preceded by 22FD, three speed
    • Model 22FDS - Sidecar Twin: 74ci F-head V-twin, 3 speed, magneto, sidecar gearing
    • Model 22FS - Sidecar Twin: 61ci F-head V-twin, 3 speed, magneto, sidecar gearing
    • Model 22J - Solo: 61ci F-head V-twin, chain drive, generator, 8.68 HP, number preceded by 22J, three speed
    • Model 22JD - Solo: 74ci F-head V-twin, chain drive, generator, 9.5 HP, number preceded by 22JD, three speed
    • Model 22JDS - Sidecar Twin: 74ci F-head V-twin, 3 speed, electrical system, sidecar gearing
    • Model 22JS - Sidecard Twin: 61ci F-head V-twin, 3 speed, electrical system, sidecar gearing
    • Model 22WF - Sport Model Solo: 35.64ci front to back horizontally opposed twin, three speed transmission, magneto
    • Model 22WJ - Solo: 35.64ci front to back horizontally opposed twin, three speed transmission, electrical system

    Specialty Models

    • Model 22FA - 'A' motor 61ci F-head V-twin, 3 speed, magneto
    • Model 22FCA - 'T' motor F-head V-twin, 3 speed
    • Model 22FDA - 'A' motor 74ci F-head V-twin, 3 speed, magneto
    • Model 22FE - 'E' motor F-head V-twin, 3 speed, magneto
    • Model 22JA - 'A' motor F-head V-twin, 3 speed, electrical system
    • Model 22JDA - 'A' motor 74 ci F-head V-twin, 3 speed, electrical system
    • Model 22JE - 'E' motor F-head V-twin, 3 speed, magneto

    Sidecars and Chassis

    • Model 22L - right-hand single-passenger sidecar
    • Model 22LC - right-hand single-passenger sidecar chassis
    • Model 22LR - right-hand single-passenger Roadster sidecar
    • Model 22LT - right hand single-passenger Tourist sidecar
    • Model 22LX - right-hand Speedster sidecar
    • Model L22L - left-hand single-passenger sidecar
    • Model L22LC - left-hand single-passenger sidecar chassis
    • Model L22LR - left-hand single-passenger Roadster Sidecar
    • Model 22M - standard commercial sidecar
    • Model 22Q - two-passenger sidecar chassis, 56in-tread
    • Model 22QA - standard closed commercial van, 56in-tread chassis
    • Model 22QB - standard open commercial van, 56in-tread chassis
    • Model 22QD - two-compartment Parcel Car, 56in-tread chassis
    • Model 22QL - right-hand two-passenger sidecar
    • Model 22QT - right-hand two-passenger Tourist sidecar

    Production: 12,759

    • Model CD - 39
    • Model F - 1824
    • Model FD - 909
    • Model J - 3183
    • Model JD - 3988
    • Model WF - 388
    • Model WJ - 455

    Options

      Schebler Deluxe carburetor
      Flat front mudguard
      Ammeter, complete
      FirestoneNon-Skid tires
      All-weather tread, Goodyear Blue Streak tires
      Goodrich Safety tread tires
      U.S. Traxion tread tires
      Heel brake (Big Twins)
      Hand brake (Sport Model)
      Luggage carrier (Big Twins)
      Front stand (Big Twins)
      Speedometer by Corbin-Brown
      Speedometer bt Johns-Manville
      Olive drab paint

    Paint Colors

      Brewster Green edged with Gold double pinstriping

    Series CD Big Singles

    First/Only Year

      Solid flywheels
      (Model CD was discontinued at the end of the model year)

    Series F and J Big Twins

    First Year

      Twelve long roller bearings for male connecting rod (late year)
      New inlet and exhaust valve springs of 'longer life'
      Revised right and left crankcases
      Revised gearbox and cover
      Revised front forks
      Double-plunger oil pump
      Manual battery-cutout switch with automatic alarm (midyear)
      Brewster Green painted crankcases
      A 1/16in compression plate beneath each cylinder on solo models; a 1/8' and a 1/16' compression plate beneath each cylinder on sidecar models

    Series CD Big Singles

    First/Only Year

      Solid flywheels
      (Model CD was discontinued at the end of the model year)

    Series FD and JD Big Twins

    First Year

      Twelve long roller bearings for male connecting rod (late year)
      New inlet and exhaust valve springs of 'longer life'
      Revised right and left crankcases
      Revised gearbox and cover
      Revised front forks
      Double-plunger oil pump (late year)
      Manual battery-cutout switch with automatic alarm (midyear)
      Brewster Green painted crankcases
      Revised cylinders that are 1/16' longer (engines after 22JD6649)
      A 1/8in and a 1/16in compression plate beneath each cylinder on sidecar models (engines 22JD6649 and under); a 1/8in plate for each cylinder after engine 22JD 6649.

    Only Year

      1/16' thick compression plates (engines 22JD6649 and under)

    Series W Sport Twins

    First Year

      31/64in rollers for the connecting rod big end (late year)
      Revised crankshaft and counterweight
      Detail changes in frame, luggage carrier, front and rear fenders, chain guard, magneto gear, battery case, and toolbox cover

    Specialty Notes

      74ci DCA engine fitted with aluminum pistons and drilled connecting rods

1923

Top

    Main Models

    • Model 23F - Solo: 61 ci F-head V-twin, chain drive, magneto ignition, 8.68 HP, number preceded by 23F, three speed
    • Model 23FS - Sidecar Twin: 61ci F-head V-twin, 3 speed, magneto, sidecar gearing
    • Model 23FD - Solo: 74ci F-head V-twin, chain drive, magneto ignition, 9.5 HP, number preceded by 23FD, three speed
    • Model 23FDS - Sidecar Twin: 74ci F-head V-twin, 3 speed, sidecar gearing, magneto
    • Model 23J - Solo: 61ci F-head V-twin, chain drive, generator, 8.68 HP, number preceded by 23J, three speed
    • Model 23JD - Solo: 74ci F-head V-twin, 3 speed, generator, 9.5 HP, number preceded by 23JD
    • Model 23JDS - Sidecar Twin: 74ci F-head V-twin, 3 speed, magneto
    • Model 23JS - Sidecar Twin: 61ci F-head V-twin, 3 speed, electrical system, sidecar gearing
    • Model 23WF - Sport Model Solo: 35.64ci (584.03cc) horizontally opposed twin, 3 speed, magneto
    • Model 23WJ - Sport Model Solo: 35.64ci (584.03cc) horizontally opposed twin, 3 speed, electrical system

    Specialty Models

    • Model 23FA - 'A' motor 61ci F-head V-twin, 3 speed, magneto
    • Model 23FCA - 61ci F-head V-twin, 3 speed, magneto
    • Model 23FDA - 'A' motor 74ci F-head V-twin, 3 speed, magneto
    • Model 23 FDCA - 74ci F-head V-twin, 3 speed, magneto
    • Model 23FE - 'E' motor 61ci F-head V-twin, 3 speed, magneto
    • Model 23JDA - 'A' motor 74ci F-head V-twin, 3 speed, electrical system
    • Model 23JDCA - 74ci F-head V-twin, 3 speed, electric ignition
    • Model 23JE - 'E' motor 61ci F-head V-twin, 3 speed, electric ignition
    • Model 23S - Track Racer: F-head single, magneto
    • Model 23T - Track Racer: F-head V-twin, magneto

    Sidecars and Chassis

    • Model 23LC - right-hand standard chassis, 42-1/2' tread
    • Model 22LR - right-hand single-passenger Roadster sidecar
    • Model 23LT - right hand single-passenger Tourist sidecar
    • Model 23LX - right-hand Speedster sidecar
    • Model L23LQ - left-hand two-passenger sidecar chassis
    • Model L23LQT - left-hand two-passenger sidecar body
    • Model L23LT - left-hand standard chassis, 46-1/2' tread
    • Model 23M - standard commercial sidecar
    • Model 23Q - two-passenger sidecar chassis, 56in-tread
    • Model 23QT - right-hand two-passenger Tourist sidecar

    Production: 18,430

    • Model F - 2822
    • Model FD - 869
    • Model J - 4802
    • Model JD - 7458
    • Model WF - 614
    • Model WJ - 481

    Options

      Schebler Deluxe carburetor
      Acetylene Lighting
      Flat front mudguard and skirt
      Ammeter, complete
      Corbin-Brown speedometer
      Johns-Manville speedometer
      Firestone Non-skid tires
      Goodyear All-weather tires
      U.S. Traxion tread tires
      Heel Brake (Big Twins)
      Hand brake (Sport model)
      Luggage carrier (Big Twins)
      Front stand (Big Twins)

    Paint Colors

      Brewster Green edged with Gold triple-line pinstriping

    Series F and J 61ci Big Twins

    First Year

      Silichrome exhaust valves
      Improved brake-pedal control
      Roller-bearing rear hub
      Larger-size generator (Models J and JS Only)
      Staylit shock-absorbing taillight (Models J and JS only)
      Hinged rear mudguard

    Series FD and JD Big Twins

    First Year

      Improved silichrome exhaust valves
      Improved cylinder heads with square cooling fins and seven cooling fins on the exhaust manifold
      Larger sized generator
      Staylit shock-absorbing taillight (Modles JD and JDS only)
      Improved brake-pedal control
      Roller-bearing rear hub
      Higend rear mudguard

    Specialty Notes

    First Year

      Bean-shaped timing case cover on Two-cam racers

1924

Top
  • No singles offered
  • Twins

    • Main Models

    • Model 24FD - twin-chain drive, magneto ignition, 9.5 HP, 74 c.i., number preceded by 24FD, three speed, cast iron pistons
    • Model 24FDS - Sidecar Twin: 74ci F-Head V-Twin with three-speed transmission, sidecar gearing, and magneto ignition and cast iron pistons
    • Model 24FDCA - twin-chain drive, magneto ignition, 9.5 HP, 74 c.i., number preceded by 24FDCA, three speed, aluminum pistons
    • Model 24FDSCA - Sidecar twin: 74ci F-Head V-Twin with three speed transmission, magneto ignition, and aluminum-alloy pistons
    • Model 24FDCB - twin-chain drive, magneto ignition, 9.5 HP, 74 c.i., number preceded by 24FDCB, three speed, iron alloy pistons
    • Model 24FE - twin-chain drive, magneto ignition, 8.68 HP, 60.34 c.i., F-Head V-Twin, number preceded by 24FE, three speed, aluminum pistons
    • Model 24FES - Sidecar Twin: 61ci F-Head V-Twin with three-speed transmission, magneto ignition, sidecar gearing, and aluminum-alloy pistons
    • Model 24JD - twin-chain drive, generator, 9.5 HP, 74 c.i., number preceded by 24JD, three speed, cast iron pistons
    • Model 24JDS - Siecar Twin: 74ci F-Head V-Twin with three-speed transmission, electrical system, sidecar gearing, and cast iron pistons
    • Model 24JDCA - twin-chain drive, generator, 9.5 HP, 74 c.i., number preceded by 24JDCA, three speed, aluminum pistnos
      • -
    • Model 24JDSCA - Sidecar Twin: 74ci F-Head V-Twin with three speed transmission, electrical system, sidecar gearing, and aluminum-alloy pistons
    • Model 24JDCB - twin-chain drive, generator, 9.5 HP, 74 c.i., number preceded by 24JDCB, three speed, iron alloy pistons
    • Model 24JE - twin-chain drive, generator, 8.68 HP, 60.34 c.i., number preceded by 24JE, three speed, aluminum pistons
    • Model 24JES - Sidecar Twin: 61ci F-Head V-Twin with three-speed transmission, electrical system, and aluminum-alloy pistons

    Sidecars and Chassis

    • 24LT - Right hand single passenger Royal Tourist Sidecar
    • 24LX - Right hand single passenger Racer Sidecar
    • 24QT - Right hand two passenger Family Delight sidecar
    • 24M - Parcel Car with hinged cover
    • L24LT - Left hand single passenger Royal Tourist Sidecar
    • L24LX - Left hand single passenger Racer Sidecar
    • L24QT - Left hand two passenger Family Delight sidecar

  • Production: 13,996
    • Model FE: 2,708
    • Model FD: 502
    • Model FDCB: 90
    • Model FDCA: 351
    • Model JE: 4,994
    • Model JD: 2,955
    • Model JDCB: 3,034
    • Model JDCA: 3,014

Options

    Iron-alloy pistons with three narrower and deeper rings (74ci)
    Zenith Carburetor
    Schebler Deluxe carburetor
    Muffler brackets designed to fit box-shaped mufflers back to 1915 models
    Corbin-Brown speedometer
    Acetylene lighting
    Flat front mudguard and skirt
    Ammeter
    Goodyear all-weather tires
    Firstone non-skid tires
    U.S. Traxion tires
    Heel brake for Big Twins
    Front stand for Big Twins
    Luggage Carrier for Big Twins

Paint Colors

    Olive-green with Maroon broad striping edged in Black witha Gold center pinstriping
Harley

Harley Transmission Serial Number Identification

Series FE and JE 61ci Big Twins

First Year

    Aluminum-alloy piston with four unevenly spaced rings
    Four-plate battery
    Revised flywheels with different balance factor
    New front exhaust pipe
    5/16in square generator brushes
    Larger generator body
    Fender center rib more prominent in height
    Front fender main section extends farther ahead of the side panels

Only Year

    Aluminum-alloy piston with four slot-cut rings
    Large box-shaped muffler
    Twelve Alemite grease fittings

Series FD and JD 74ci Big Twins

First Year

    Revised flywheels with different balance factor
    New front and rear exhaust pipes
    5/16in square generator brushes
    Larger generator body
    Four-Plate battery
    Fender center rib more prominent in height
    Front fender main section extends farther ahead of the side panels
    Running gear lubricated by an Alemite gun

Only Year

    Large box-shaped muffler
    Twelve Alemite grease fittings

Specialty Notes

First Year

    Valves now operating with direct action from lobes on Two-cam Racer
    Roller tappets on Two-cam Racer
    Hollow pushrods on Two-cam Racer
    Removable lifter blocks bolted to crankcase on Two-cam Racer

1925

Top
  • No singles offered
  • Twins
  • Model 25FE - twin-chain drive, magneto ignition, 8.68 HP, 60.34 c.i., number preceded by 25FE, three speed, iron alloy pistons
  • Model 25FDCB - twin-chain drive, magneto ignition, 9.5 HP, 74 c.i., number preceded by 25FDCB, three speed, iron alloy pistons
  • Model 25JDCB - twin-chain drive, generator, 9.5 HP, 74 c.i., number preceded by 25JDCB, three speed, iron alloy pistons
  • Model 25JE - twin-chain drive, generator, 8.68 HP, 60.34 c.i., number preceded by 25JE, three speed, iron alloy pistons
  • Production: 16,929

1926

Top
  • Twins
  • Model 26F - twin-chain drive, magneto ignition, 8.68 HP, 60.34 c.i., number preceded by 26F, three speed, iron alloy pistons
  • Model 26FD - twin-chain drive, magneto ignition, 9.5 HP, 74 c.i., number preceded by 26FD, three speed, iron alloy pistons
  • Model 26J - twin-chain drive, generator, 8.68 HP, 60.34 c.i., number preceded by 26J, three speed, iron alloy pistons
  • Model 26JD - twin-chain drive, generator, 9.5 HP, 74 c.i., number preceded by 26JD, three speed, iron alloy pistons
  • Production: 26,354

1927

TopHarley davidson transmission serial numbers
  • Twins
  • Model 27F - twin-chain drive, magneto ignition, 8.68 HP, 60.34 c.i., number preceded by 27F, three speed, iron alloy pistons
  • Model 27FD - twin-chain drive, magneto ignition, 9.5 HP, 74 c.i., number preceded by 27FD, three speed, iron alloy pistons
  • Model 27J - twin-chain drive, generator, 8.68 HP, 60.34 c.i., number preceded by 27J, three speed, iron alloy pistons
  • Model 27JD - twin-chain drive, generator, 9.5 HP, 74 c.i., number preceded by 27JD, three speed, iron alloy pistons
  • Production: 19,911

1928

Gm Transmission Casting Numbers

Top
  • Singles
  • Model 28A - single-chain drive, magneto ignition, 3.31 HP, 21.098 c.i., number preceded by 28A, SV, Dow metal pistons
  • Model 28AA - single-chain drive, magneto ignition, 3.31 HP, 21.098 c.i., number preceded by 28AA, OHV, Dow metal pistons
  • Model 28B - single-chain drive, generator, 3.31 HP, 21.098 c.i., number preceded by 28B, SV, Dow metal pistons
  • Model 28BA - single-chain drive, generator, 3.31 HP, 21.098 c.i., number preceded by 28BA, OHV, Dow metal pistons
  • Twins
  • Model 28F - twin-chain drive, magneto ignition, 8.68 HP, 60.34 c.i., number preceded by 28F, three speed, iron alloy pistons
  • Model 28FD - twin-chain drive, magneto ignition, 9.5 HP, 74 c.i., number preceded by 28FD, three speed, iron alloy pistons
  • Model 28J - twin-chain drive, generator, 8.68 HP, 60.34 c.i., number preceded by 28J, three speed, iron alloy pistons
  • Model 28JD - twin-chain drive, generator, 9.5 HP, 74 c.i., number preceded by 28JD, three speed, iron alloy pistons
  • Model 28JXL - twin-chain drive, generator, 8.68 HP, 60.34 c.i., number preceded by 28JXL, three speed, Dow metal pistons
  • Model 28JDXL - twin-chain drive, generator, 9.5 HP, 74 c.i., number preceded by 28JDXL, three speed, Dow metal pistons
  • Model 28JH - twin-chain drive, two cams, generator, 8.68 HP, 60.34 c.i., number preceded by 28JH, three speed, Dow metal pistons
  • Model 28JDH - twin-chain drive, two cams, generator, 9.5 HP, 74 c.i., number preceded by 28JDH, three speed, iron alloy pistons
    • (Note: All 61 and 74 ci models were offered with 25x3.85 tire sizes; the JD models were offered with these tire sizes standard and with 27x3.85 tires optional. Tire size for singles was 26x3.30)
  • Production: 22,350

Harley Transmission Serial Numbers Where

1929

Top

Dodge Transmission Serial Number

  • Singles
  • Model 29A - single-chain drive, magneto ignition, 3.31 HP, 21.098 c.i., number preceded by 29A, SV, Dow metal pistons
  • Model 29AA - single-chain drive, magneto ignition, 3.31 HP, 21.098 c.i., number preceded by 29AA, OHV, Dow metal pistons
  • Model 29B - single-chain drive, generator, 3.31 HP, 21.098 c.i., number preceded by 29B, SV, Dow metal pistons
  • Model 29BA - single-chain drive, generator, 3.31 HP, 21.098 c.i., number preceded by 29BA, OHV, Dow metal pistons
  • Twins
  • Model 29D - twin-chain drive, generator, No HP Given, 45.32 c.i., number preceded by 29D, three speed, Dow metal pistons
  • Model 29F - twin-chain drive, magneto ignition, 8.68 HP, 60.34 c.i., number preceded by 29F, three speed, iron alloy pistons
  • Model 29FD - twin-chain drive, magneto ignition, 9.5 HP, 74 c.i., number preceded by 29FD, three speed, iron alloy pistons
  • Model 29J - twin-chain drive, generator, 8.68 HP, 60.34 c.i., number preceded by 29J, three speed, iron alloy pistons
  • Model 29JD - twin-chain drive, generator, 9.5 HP, 74 c.i., number preceded by 28JD, three speed, iron alloy pistons
  • Model 29JXL - twin-chain drive, generator, 8.68 HP, 60.34 c.i., number preceded by 29JXL, three speed, Dow metal pistons
  • Model 29JDXL - twin-chain drive, generator, 9.5 HP, 74 c.i., number preceded by 29JDXL, three speed, Dow metal pistons
  • Model 29JH - twin-chain drive, two cams, generator, 8.68 HP, 60.34 c.i., number preceded by 29JH, three speed, Dow metal pistons
  • Model 29JDH - twin-chain drive, two cams, generator, 9.5 HP, 74 c.i., number preceded by 29JDH, three speed, iron alloy pistons
    • (Note: 45 ci models offered with 25x3.85 tires, standard; 61 and 74 ci models were offered with 27x3.85 tires, standard; No optional sizes listed)
  • Production: 21,142