1936–1947 Harley-Davidson Knucklehead Models
1936–1947 Harley-Davidson Knucklehead models including EL and FL with production numbers, model variations, VIN data, and specs.
Explore Other Eras: 1903–1929 Early Era | 1930–1936 V-Series | 1936–1947 Knucklehead | 1948–1965 Panhead
Quick Navigation
1936 | 1937 | 1938 | 1939 | 1940 | 1941 | 1942 | 1943 | 1944 | 1945 | 1946 | 1947
Overview
The Knucklehead era spans Harley-Davidson’s pre-war OHV development, the expansion of the 74 OHV family, wartime civilian interruptions, and the post-war return that leads directly into the 1948 Panhead era. This page serves as a year-by-year Knucklehead model and production reference, organized by Knucklehead / OHV models and the other Harley-Davidson models that appeared alongside them.
VIN Information
Knucklehead-era engine numbers identify the year and engine family, but they do not fully describe every final motorcycle configuration. Sidecar gearing designations, special-use variants, and certain marketed model names are not always reflected exactly in the stamped serial number, so the VIN should be used as a starting point rather than a complete description. For complete engine number decoding, see the Harley-Davidson VIN decoder and serial number guide.
1936 Harley-Davidson Models
Quick Links: Paint Options
Platform: First Knucklehead year (transition from V-Series)
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo (first year)
- E 61 OHV Twin, Medium Compression
- ES 61 OHV Twin, Sidecar Gearing (Medium Compression)
Other Models
- VL 74 Twin, Special Sport Solo
- V 74 Twin, Medium Compression
- VS 74 Twin, Medium Compression, Sidecar Gearing
- VLD 74 Twin, Sport Solo
- VLDH 80 Twin, Sport Solo
- VH 80 Twin, Medium Compression
- VHS 80 Twin, Medium Compression, Sidecar Gearing
- W 45 Twin, Low Compression
- WL 45 Twin, High Compression
- WS 45 Twin, Sidecar Gearing
- G Servi-Car, with Tow Bar
- GA Servi-Car, less Tow Bar
- LE Sidecar
- LS Sidecar
- M Package Truck
- MO Package Truck
- MC Chassis Only
Model / VIN Notes
- 1936 is the first year of the Knucklehead engine (EL), appearing alongside the outgoing V-Series flathead big twins.
- The presence of E and ES alongside EL shows that multiple compression and gearing variants were already offered in the first year.
- This year represents a true overlap period where OHV and flathead big twins are both actively produced.
Production Numbers
- E — 152
- EL — 1,516
- ES — 26
1937 Harley-Davidson Models
Quick Links: Paint Options
Platform: Early pre-war Knucklehead / Flathead overlap
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo
- E 61 OHV Twin, Solo, Medium Compression
- ES 61 OHV Twin, Medium Compression, Sidecar Gearing
Other Models
- WL 45 Twin, Sport Solo, High Compression
- WLD 45 Twin, Sport Solo, Extra High Compression
- WLDR 45 Twin, Competition Special
- W 45 Twin, Low Compression
- WS 45 Twin, Low Compression, Sidecar Gearing
- UL 74 Twin, Special Sport Solo
- U 74 Twin, Solo, Medium Compression
- US 74 Twin, Medium Compression, Sidecar Gearing
- ULH 80 Twin, Special Sport Solo
- UH 80 Twin, Solo, Medium Compression
- UHS 80 Twin, Medium Compression, Sidecar Gearing
- G Servi-Car, with Tow Bar
- GA Servi-Car, less Tow Bar
- GD Servi-Car, large Commercial Body, less Tow Bar
- GDT Servi-Car, large Commercial Body, with Tow Bar
- GE Servi-Car, large Commercial Body, with Tow Bar, Air Tank and Combination Bumper and Tire Carrier
- LE Sport Sidecar for 61, 74 and 80 Twins
- LS Sidecar for 45 Twin
- M Package Truck with Cover
- MO Package Truck without cover
- LEC LE Chassis only
- LSC LS Chassis only
- MC M/MO Chassis only
Model / VIN Notes
- 1937 is the first year in this reference and shows the 61 OHV Knucklehead coexisting with a very broad flathead and utility lineup.
- Sidecar gearing designations such as WS, US, UHS, and ES are model identifiers, but the sidecar suffix itself is not stamped into the VIN.
- This year also includes an especially wide range of Servi-Car, sidecar, chassis, and package-truck listings.
Production Numbers
- E — 126
- EL — 1,829
- ES — 70
1938 Harley-Davidson Models
Quick Links: Paint Options
Platform: Pre-war refinement
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo
- ES 61 OHV Twin, Medium Compression, Sidecar Gearing
Other Models
- WL 45 Twin, Sport Solo, High Compression
- WLD 45 Twin, Sport Solo, Extra High Compression
- WLDR 45 Twin, Competition Special
- UL 74 Twin, Special Sport Solo
- U 74 Twin, Solo, Medium Compression
- US 74 Twin, Medium Compression, Sidecar Gearing
- ULH 80 Twin, Special Sport Solo
- UH 80 Twin, Solo, Medium Compression
- UHS 80 Twin, Medium Compression, Sidecar Gearing
- G Servi-Car, with Tow Bar
- GA Servi-Car, less Tow Bar
- GD Servi-Car, large Commercial Body, less Tow Bar
- GDT Servi-Car, large Commercial Body, with Tow Bar
- LE Sport Sidecar for 61, 74 and 80 Twins
- M Package Truck with Cover
- MO Package Truck without cover
- MC M/MO Chassis only
- MWC Package Truck Chassis, 57-7/8” Tread
Model / VIN Notes
- 1938 narrows the OHV listings to EL and ES while the surrounding flathead and commercial range remains extensive.
- As in 1937, sidecar gearing suffixes are part of the sales designation rather than the stamped engine number.
- The package-truck and chassis listings also expand with the appearance of MWC.
Production Numbers
- EL — 2,289
- ES — 189
1939 Harley-Davidson Models
Quick Links: Paint Options
Platform: Pre-war refinement
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo
- ES 61 OHV Twin, Medium Compression, Sidecar Gearing
Other Models
- WL 45 Twin, Sport Solo, High Compression
- WLD 45 Twin, Sport Solo, Extra High Compression
- WLDR 45 Twin, Competition Special
- UL 74 Twin, Special Sport Solo
- U 74 Twin, Solo, Medium Compression
- US 74 Twin, Medium Compression, Sidecar Gearing
- ULH 80 Twin, Special Sport Solo
- UH 80 Twin, Solo, Medium Compression
- UHS 80 Twin, Medium Compression, Sidecar Gearing
- G Servi-Car, with Tow Bar
- GA Servi-Car, less Tow Bar
- GD Servi-Car, large Commercial Body, less Tow Bar
- GDT Servi-Car, large Commercial Body, with Tow Bar
- LE Sport Sidecar for 61, 74 and 80 Twins
- M Package Truck with Cover
- MO Package Truck without cover
- MC M/MO Package Truck Chassis Only
- MWC Package Truck Chassis, 57-7/8” Tread
Model / VIN Notes
- 1939 continues the same basic EL / ES OHV structure while preserving the wide flathead and commercial support range.
- The sidecar-gearing suffix remains a model description rather than a VIN-stamped engine feature.
Production Numbers
- EL — 2,695
- ES — 214
1940 Harley-Davidson Models
Quick Links: Paint Options
Platform: Late pre-war
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo
- ES 61 OHV Twin, Medium Compression, Sidecar Gearing
Other Models
- WL 45 Twin, Sport Solo, High Compression
- WLD 45 Twin, Special, Sport Solo
- WLDR 45 Twin, Competition Special
- UL 74 Twin, Special Sport Solo
- U 74 Twin, Solo, Medium Compression
- US 74 Twin, Medium Compression, Sidecar Gearing
- ULH 80 Twin, Special Sport Solo
- UH 80 Twin, Solo, Medium Compression
- UHS 80 Twin, Medium Compression, Sidecar Gearing
- G Servi-Car, with Tow Bar
- GA Servi-Car, less Tow Bar
- GD Servi-Car, large Commercial Body, less Tow Bar
- GDT Servi-Car, large Commercial Body, with Tow Bar
- LE Sport Sidecar for 61, 74 and 80 Twins
- M Package Truck with Cover
- MO Package Truck without cover
Model / VIN Notes
- 1940 is the last pre-war year before the 74 OHV FL family appears.
- The 61 OHV Knucklehead remains the only OHV family listed, while flatheads still dominate the broader range around it.
Production Numbers
- EL — 3,893
- ES — 176
1941 Harley-Davidson Models
Quick Links: Paint Options
Platform: Peak pre-war development
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo
- E 61 OHV Twin, Medium Compression
- FL 74 OHV Twin, Special Sport Solo
- F 74 OHV Twin, Medium Compression
Other Models
- WL 45 Twin, High Compression
- WLD 45 Twin, Sport Solo
- WLDR 45 Twin, Special Sport Solo
- UL 74 Twin, Special Sport Solo
- U 74 Twin, Solo, Medium Compression
- ULH 80 Twin, Special Sport Solo
- UH 80 Twin, Solo, Medium Compression
- G Servi-Car, with Tow Bar
- GA Servi-Car, less Tow Bar
- GD Servi-Car, large Commercial Body, less Tow Bar
- GDT Servi-Car, large Commercial Body, with Tow Bar
- LE Sport Sidecar for 61, 74 and 80 Twins
- M Package Truck with Cover
- MC Chassis Only for Package Truck
Model / VIN Notes
- 1941 is the breakthrough year for the 74 OHV FL / F family in the Knucklehead era.
- The year sheet also reintroduces the lower-compression E model alongside EL, giving the 61 OHV family a broader spread.
Production Numbers
- EL — 2,280
- ES — 261
- FL — 2,452
- FS — 156
1942 Harley-Davidson Models
Quick Links: Paint Options
Platform: Transition year
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo
- E 61 OHV Twin, Medium Compression
- FL 74 OHV Twin, Special Sport Solo
- F 74 OHV Twin, Medium Compression
Other Models
- WL 45 Twin, High Compression
- WLD 45 Twin, Sport Solo
- UL 74 Twin, Special Sport Solo
- U 74 Twin, Solo, Medium Compression
- G Servi-Car, with Tow Bar
- GA Servi-Car, less Tow Bar
- LE Sport Sidecar for 61 and 74
- M Package Truck
- MC Chassis Only for Package Truck
Model / VIN Notes
- 1942 still carries both 61 OHV and 74 OHV Knuckleheads, but civilian production is already being compressed by wartime restrictions.
- The notes for this year also show that sidecar gearing and 45 sidecar arrangements could still be specified even when not represented directly in the serial number.
- The presence of ELA and ELC in the production figures shows how wartime coding and production categories could become more complicated than the simple retail model listings imply.
Production Numbers
- EL — 620
- ELA — 8
- ELC — 44
- ES — 164
- FL — 799
- FS — 107
1943 Harley-Davidson Models
Quick Links: Paint Options
Platform: Wartime production
Knucklehead / OHV Models
- Officially no civilian models were built in 1943
- The exact civilian models are unknown
Other Models
- No confirmed civilian lineup listed
Model / VIN Notes
- 1943 is treated as a wartime interruption year for civilian production.
- The source notes acknowledge that at least a small number of civilian machines may have existed, but the exact model breakdown is not known.
Production Numbers
- No civilian models produced
1944 Harley-Davidson Models
Quick Links: Paint Options
Platform: Wartime / WPB-approved orders
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo
- E 61 OHV Twin, Medium Compression
- FL 74 OHV Twin, Special Sport Solo
- F 74 OHV Twin, Medium Compression
Other Models
- UL 74 Twin, High Compression Solo
- U 74 Twin, Medium Compression
- LE Sport Sidecar for 61 and 74 Twins
- M Package Truck
- MC Chassis Only for Package Truck
Model / VIN Notes
- 1944 civilian availability is limited to WPB-approved orders rather than a normal retail lineup.
- The year sheets make it clear that 45 models were not officially offered to the public, even though the possibility of extremely limited non-military examples cannot be ruled out completely.
- This is another year where what was technically possible and what was publicly cataloged are not identical.
Production Numbers
- EL — 116
- ES — 105
- FL — 172
- FS — 67
1945 Harley-Davidson Models
Quick Links: Paint Options
Platform: Post-war restart
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo
- E 61 OHV Twin, Medium Compression
- ES 61 OHV Twin, Sidecar Gearing (Med. Comp.)
- FL 74 OHV Twin, Special Sport Solo
- F 74 OHV Twin, Medium Compression
- FS 74 OHV Twin, Sidecar Gearing (Med. Comp.)
Other Models
- WL 45 Twin, High Compression
- UL 74 Twin, High Compression Solo
- U 74 Twin, Medium Compression
- US 74 Twin, Medium Compression, Sidecar Gearing
- G Servi-Car, with Tow Bar
- GA Servi-Car, less Tow Bar
- LE Sport Sidecar for 61 and 74
- M Package Truck
- MC Chassis Only for Package Truck
Model / VIN Notes
- 1945 marks the return of a fuller civilian lineup after wartime interruption.
- The post-war sheets again show the familiar difference between sales/configuration suffixes and the actual stamped VIN.
- The notes for this year also reflect the material and tire constraints still affecting immediate post-war production.
Production Numbers
- EL — 398
- ES — 282
- FL — 619
- FS — 131
1946 Harley-Davidson Models
Quick Links: Paint Options
Platform: Post-war stabilization
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo
- E 61 OHV Twin, Medium Compression
- ES 61 OHV Twin, Sidecar Gearing (Medium Compression)
- FL 74 OHV Twin, Special Sport Solo
- F 74 OHV Twin, Medium Compression
- FS 74 OHV Twin, Sidecar Gearing (Medium Compression)
Other Models
- WL 45 Twin, High Compression
- UL 74 Twin, High Compression Solo
- U 74 Twin, Medium Compression
- US 74 Twin, Medium Compression, Sidecar Gearing
- G Servi-Car, with Tow Bar
- GA Servi-Car, less Tow Bar
- LE Sport Sidecar for 61 and 74 Twins
- M Package Truck
- MC Chassis Only for Package Truck
Model / VIN Notes
- 1946 reflects a more stabilized post-war civilian range built around both 61 OHV and 74 OHV Knuckleheads.
- The same post-war supply and equipment realities still appear in the background notes, but the model structure itself is much stronger than in 1945.
Production Numbers
- EL — 2,098
- ES — 244
- FL — 3,986
- FS — 418
1947 Harley-Davidson Models
Quick Links: Paint Options
Platform: Final Knucklehead year
Knucklehead / OHV Models
- EL 61 OHV Twin, Special Sport Solo
- E 61 OHV Twin, Medium Compression
- ES 61 OHV Twin, Sidecar Gearing (Medium Compression)
- FL 74 OHV Twin, Special Sport Solo
- F 74 OHV Twin, Medium Compression
- FS 74 OHV Twin, Sidecar Gearing (Medium Compression)
Other Models
- WL 45 Twin, High Compression
- UL 74 Twin, High Compression Solo
- U 74 Twin, Medium Compression
- US 74 Twin, Medium Compression, Sidecar Gearing
- G Servi-Car, with Tow Bar
- GA Servi-Car, less Tow Bar
- LE Sport Sidecar for 61 and 74 Twins
- M Package Truck
- MC Chassis Only for Package Truck
Model / VIN Notes
- 1947 is the final Knucklehead year before the Panhead arrives in 1948.
- The model sheet shows a mature post-war lineup with both OHV and side-valve holdovers still present together.
- The sidecar-gearing suffix still functions as a model designation rather than a direct serial-number element.
Production Numbers
- EL — 4,117
- ES — 237
- FL — 6,893
- FS — 401
Model Lifecycle Summary
61 OHV Knucklehead Family
- E / EL / ES appear throughout the era, with EL and ES represented in production figures from 1937 onward.
- The lower-compression E model is explicitly listed in the year sheets for 1937, 1941, 1942, and the post-war years.
74 OHV Knucklehead Family
- FL / F / FS appear in 1941 and continue through 1947.
- The arrival of the FL family marks the major expansion of the OHV Knucklehead lineup.
45 Side-Valve Family
- WL-based models are strong in the pre-war years, disappear during wartime restrictions, and return after the war.
74 / 80 Side-Valve Families
- U / UL / US and UH / ULH / UHS anchor the pre-war side-valve big-twin range.
- These lines are sharply reduced or absent during wartime years, then return in more limited form after the war.
Utility and Commercial Support Models
- Servi-Car, sidecar, chassis, and package-truck listings are strongest before the war and return selectively after it.
- These support models are an important part of the Knucklehead-era catalog, even though they are not motorcycle models in the same sense as EL or FL.