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Flathead facts & figures


Model Year Description
W 1937 - 1952 low compression 45 Solo
WL 1937 - 1952 high compression 45 Sport Solo
WLD 1973 - 1942 extra high compression 45 Sport Solo
WLA 1940 - 1945 and 1949 - 1952 US Army low compression 45 Solo
WLC 1942 - 1943 Canadian Army low compression 45 Solo
WLH 1950 - 1951 Special batch for Dutch Military Police
WLJ 1951 Special batch
WR   Race model
G 1937 - 1973 Servi-Car with tow bar
GA 1937 - 1973 Servi-Car without tow bar
GD 1937 - 1941 large body Servi-Car without tow bar
GDT 1937 - 1941 large body Servi-Car with tow bar
 
Flathead, 1940 - 1952 Civilian models
Model
Compression
  Number of cylinders
2
WL (Aluminum heads)
6 to 1
  Cylinder bore
2 inches
WL (Iron heads)
4.75 to 1
  Piston displacement (739.46 cc)
45.12 cu.in.
G (Servi-car)
4.75 to 1
  Stroke (96.85 mm)
3 13/16 inches
Average delivered power and RPM: 25 HP at 4500 RPM   Wheelbase
57 ½ inches
 
Gear Ratios
 
Tire Inflation Pressures
  Motor
Sprocket
Clutch
Sprocket
Counter-
shaft
Sprocket
Rear
Wheel
Sprocket
High
Gear
Ratio
Solo (iron heads)
31
59
17
41
4.59 to 1
Solo (alu. heads)
30
59
17
41
4.74 to 1
Sidecar
27
59
17
41
5.27 to 1
Servi-Car
22
59
17
37
5.84 to 1
   
Solo 4"00 tire Front 12 lbs. Rear 14 lbs.
  5"00 tire Front 12 lbs. Rear 12 lbs.
Servi-Car 4"00 tire Front 12 lbs. Rear 20 lbs.
  5"00 tire Front 12 lbs. Rear 16 lbs.
 
Sources: see also Books
Bruce Palmer: How to restore your Harley-Davidson
Greg Field: Original Harley-Davidson Panhead
Peter Henshaw: The legend of Harley-Davidson
Harley-Davidson Panhead Service Manual - 1948 - 1957
and various other sources
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