1957 Sportster

Vehicle Identification Number (VIN)

  • The serial number is stamped on the left side of the engine case. The first 5 or 6 digits represent the year and model 1)

The Sportster XL was introduced as “a modern, up-to-date power plant.” www.motorcycleclassics.com_media_images_mcc_editorial_articles_magazine_articles_2011_05-01_1957_harley-davidson_sportster_xl_sportster-1.jpg

In 1952, the W models were replaced with the revered 45-cubic inch side-valve K series. The new K-models included an integrated four-cam engine and four-speed transmission design, along with foot shift, swingarm rear suspension, and telescopic front forks to compete with smaller, sportier motorcycles coming mainly from Great Britain. Essentially, the new XL motor was an updated K-model engine with larger displacement, overhead valves and higher compression. - Harley-Davidson Archives Copyright H-D 2)

Number produced: 19833)

Original Price: $1103

Specifications

1957-sportster-engine.jpg

  • Model Designation: XL

Engine

  • Engine type: 4 cycle Overhead Valves, 45 degree V2 4)
  • Kick start only 5)
  • Displacement: 55 ci / 883 cc (900 cc advertised) 6)
  • Compression: 7.5:1 7)
  • Hemi-spherical style heads
  • Bore: 3 in / 76.2 mm 8)9)
  • Stroke: 3.8125 in / 96.8 mm 10)11)
  • 90 Degree Valve Angle
  • Horsepower: 42 @ 5,500rpm 12)
  • Torque: 48 ft-lb @ 3600 RPM 13)
  • 4 Cams
  • Oil pump pressure: 6 psi @ 20 MPH 14)
  • Fuel System: Linkert DC carburetor 15)
  • Ignition: Ignition spark is produced by operation of a circuit breaker, ignition coil and spark plugs. The breaking of a single set of breaker points by a double lobe cam on the timer shaft determines the spark timing. The narrow lobe times the front cylinder while the wider lobe times the rear. 16)

Capacities

  • Fuel capacity: 4 gal / 15.14 l17)
  • Oil Capacity: 3 qts. / 2.83 l 18)
  • Transmission Capacity: 1.5 pints / .71 l 19)
  • MPG: 50mpg (est.)20)

Clutch

  • Multi-Disc dry clutch-pack with alternate steel and fiber friction plates.21)

Dimensions

  • Weight: 495 lb / 225 kg22)
  • Wheelbase: 56.5 in / 143.51 cm 23)
  • Overall Length: 87 in / 221 cm 24)
  • Overall Width: 34 in / 86.36 cm 25)
  • Overall Height: 40.5“ 26)
  • Road Clearance: 2.5 in min / 6.35 c minimum, 4-5/8 in max 27)
  • Saddle height 26-7/8“ to 29”

Drivetrain

  • Constant Mesh - Foot shift
  • Speeds - 4 Forward
  • Number of Sprocket Teeth
    • Engine: 34 28)
    • Clutch: 59 29)
    • Transmission: 21 30)
    • Rear Wheel: 51 31)
  • Gear Ratios
    • 1st: 10.63:1 32)
    • 2nd: 7.69:1 33)
    • 3rd: 5.82:1 34)
    • 4th: 4.21:1 35)

Tires

  • Front and rear: 3.50 x 18
  • Tire pressure (based on a rider weighing app. 150 lbs or more)
  • For each 50 lbs of overload, increase rear tire pressure by 2 lbs., front by 1 lb. 36)but not exceeding max tire pressure.
    • Front: 14 psi / .96 bar
    • Rear: 18 psi / 1.24 bar

Models

  • XL

Colors

  • Pepper Red / Black Tank Panels37)
  • Skyline Blue / Birch White Tank Panels38)
  • Birch White / Black Tank Panels39)
  • Black / Pepper Red Tank Panels40)
1)
HD Parts Catalog XLH/XLCH-1000 #(99451-78)
3)
[[http://www.caimag.com/forum/showthread.php?5757-Help-with-1957-xl-sportster/page2|http://www.caimag.com/forum/showthread.php?5757-Help-with-1957-xl-sportster/page2]]
4) , 12) , 17) , 18) , 19) , 23) , 24) , 25)
Harley-Davidson 1957 - 1969 Service Manual
5) , 21)
1957-1969 HD FSM pg 4A-3
6) , 7) , 8) , 10) , 13) , 16) , 27) , 28) , 29) , 30) , 31) , 32) , 33) , 34) , 35)
1957-1969 HD FSM pg 1A-3
14)
1957-1969 HD FSM pg 3A-11
15)
1957-1969 HD FSM pg 3F-7
26) , 36)
1959-1964 HD FSM pg 1A-3
41)
http://www.harleykmodel.com/literature/spare-parts-catalogs/documents/99451-57/99451-57.pdf
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