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1957 Sportster

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 1)

Number produced: 19832)

Original Price: $1103

Vehicle Identification

Frame Numbers

There was no frame identification for purpose of ownership on 1957-1969 model Sportsters.
However, there were stampings on the different parts of the frame combined with certain features that can be used to date the frame.
Click Here to view Ironhead Frame Identification in the Sportsterpedia.

Engine Serial Numbers

The only numbers for the purpose of identification were on the engine case.

  • For 1957-1961 models, the engine serial number is stamped on the left side of the engine case between the two cylinders.
    First 4 or 5 digits are the year and bike model followed by a series of 4 or 5 numbers that established the individual serial number for each bike.

Click Here for more specific information on serial numbers and VINs in the Sportsterpedia.

Engine Serial Number for 1957 Sportsters
Model Year
(first 2 digits)
Model
(next few digits)
(up to 4)
Sequential
Serial#
(remaining digits)
57XL (example)
12345
Example: (57XL 12345) indicates a 1957 XL model and is stamped on the Left Engine Case Between the Cylinders 3)
Example Serial Number on Engine Reads: 57XL12345
57 XL 12345

Illustrations

The following illustrations are displayed for historic and period specific parts identification only. Refer to the original OEM documents for additional information. 4)
Click on any illustration below to enlarge.

1957_xl883_illust_engine.jpg

Specifications

Model Designation

  • XL

Dimensions

  • Wheelbase: 56.5 in / 143.51 cm 5)
  • Overall Length: 87 in / 221 cm
  • Overall Width: 34 in / 86.36 cm
  • Overall Height: 40.5 in
  • Saddle height 26-7/8 in to 29 in / 68.26 cm to 73.66 cm
  • Road Clearance: 2.5 in to 4-5/8 in / 6.35 cm to 11.74 cm

Engine

  • Engine type: 4 cycle Overhead Valves, 45 degree V2 6)
  • Displacement: 53.9 ci / 883 cc (900 cc advertised)
  • Compression Ratio: 7.5:1
  • Bore: 3 in / 76.2 mm
  • Stroke: 3.8125 in / 96.8 mm
  • Horsepower: 42 @ 5,500 rpm
  • Taxable Horsepower: 7.2
  • Torque: 48 ft/lb @ 3.600 RPM
  • Weight: 204 lbs.
  • 4 Cams
  • Oil Pump: Gear driven type oil pump. Click Here for the IH Oil Pump section of the Sportsterpedia.
  • Oil pump pressure (gauge mounted in place of oil pressure switch):
    • Idle, with spark retarded (Min: 3-7 psi)
    • Normal riding conditions: 10-14 psi (6 psi at 20 mph)
  • Fuel System: Linkert DC carburetor. Click Here for the main Ironhead carb page in the Sportsterpedia.
  • Spark Plugs
    • #4 for everyday use.
    • #5 for hard service.

Capacities

  • Fuel capacity: 4.1 gal / 15.52 l7)
  • Oil Capacity: 3 qts. / 2.83 l
  • Transmission Capacity: 1.5 pints / .71 l

Clutch

  • Multi-Disc dry clutch-pack with alternate steel and fiber friction plates.8)

Drivetrain

  • Constant Mesh - right side foot shift 9)
  • Speeds - 4 Forward
  • Number of Sprocket Teeth
    • Engine: 34
    • Clutch: 59
    • Transmission: 21
    • Rear Wheel: 51
  • Standard Gear Ratios
    • 1st: 10.63:1
    • 2nd: 7.69:1
    • 3rd: 5.82:1
    • 4th: 4.21:1

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. 10)but not exceeding max tire pressure.
    • Front: 14 psi / .96 bar
    • Rear: 18 psi / 1.24 bar

Model

  • XL

Colors

  • Pepper Red / Black Tank Panels11)
  • Skyline Blue / Birch White Tank Panels12)
  • Birch White / Black Tank Panels13)
  • Black / Pepper Red Tank Panels14)
2)
[[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]]
3)
1953-1963 HD Parts Catalog backside of front cover
4)
illustrations from various academic journals
5) , 6)
Harley-Davidson 1957 - 1969 Service Manual
7)
Harley-Davidson 1960 Sportster Service Manual
8)
1957-1969 HD FSM pg 4A-3
9)
1957-1969 HD FSM pg 1A-3
10)
1959-1964 HD FSM pg 1A-3
15)
http://www.harleykmodel.com/literature/spare-parts-catalogs/documents/99451-57/99451-57.pdf
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