Vintage Harley-Davidson Reference Materials
Harley-Davidson Knucklehead Models & Production Reference (1936–1947)
Reference guide to Harley-Davidson Knucklehead models produced from 1936 through 1947, including OHV twin models, VIN interpretation notes, production figures where available, other models sold during the same period, and links to the correct paint and emblem guides.
The Knucklehead era (1936–1947) represents Harley-Davidson’s first OHV big twin engines and continued alongside a range of other Harley models including flatheads, Servi-Cars, and sidecar chassis. This reference consolidates model designations, production numbers, VIN interpretation, and related models to provide a comprehensive view of all machines produced in this period.
Knucklehead Model Designations & VIN Notes
| Code | Meaning | VIN Note |
|---|---|---|
| EL | 61 OHV Twin | Appears in VIN |
| FL | 74 OHV Twin | Appears in VIN |
| S | Sidecar Gearing designation | Not in VIN |
| F | Foot shift designation | Not in VIN |
| C | Sidecar chassis designation | Not in VIN |
Production figures listed below are fiscal-year based where available and may not represent exact model-year totals.
Harley-Davidson Knucklehead Models by Year
1936–1937
OHV Twins (Knucklehead)
- EL — 61 OHV Sport Solo
- FL — 74 OHV Sport Solo
Other Models Available
- WL — 45 Twin
- UL — 74 Twin
- G — Servi-Car with Reverse Gear
1938–1939
- EL / FL OHV twins continued
Other Models Available
- WL / UL variants, Servi-Car, sidecar chassis (LE / LEC)
1940–1941
- EL / FL OHV twins
Other Models Available
- WL / UL, Servi-Car, LE / LEC
1942–1945 (Wartime)
- Production focused on military models (WLA, Servi-Car)
- OHV twins limited civilian production
1946–1947
- EL / FL OHV twins resumed full civilian production
Other Models Available
- WL / UL / Servi-Car / LE / LEC / Utility models