The Vintage Motorcycles
Specialists in antique, classic, veteran and vintage motorcycles.
Specialists in antique, classic, veteran and vintage motorcycles.
The 1938 Terrot Model HDA 350 is a distinctive French military motorcycle produced by Terrot of Dijon. The HDA was the military version of the company's 350 cc HD, and contemporary model references place the HDA in military production from 1938 through approximately 1940. The motorcycle uses a 350 cc single-cylinder side-valve engine, a three-speed gearbox, chain final drive, and a rigid rear frame with a period parallelogram-style front fork.
The HDA was developed for military service during a period when the French Army was expanding its motorcycle fleet. It retained the basic mechanical architecture of the civilian HD while receiving military-oriented equipment and specification.
Its combination of a relatively simple 350 cc side-valve engine, robust chassis, hand-operated gear change, drum brakes, and military equipment made the HDA well suited to dispatch, reconnaissance, liaison, and general utility duties.
Today, the 1938 Terrot HDA 350 is an interesting and relatively uncommon example of French pre-war military motorcycle engineering.
Terrot was one of France's major motorcycle manufacturers and was based in Dijon. During the 1930s, the company produced a wide range of motorcycles, from lightweight machines to large-capacity touring and sporting models.
The 350 cc HD was one of Terrot's important utility motorcycles during this period. The HDA was derived from the HD and adapted for military service.
Historical Terrot model references identify the HDA as a military 350 cc model produced from 1938 to approximately 1940. The HDA was closely related mechanically to the civilian HD, while military examples received appropriate equipment and finishes.
Military production became increasingly important to Terrot as Europe moved toward the Second World War. Terrot subsequently supplied motorcycles to the French military, and wartime production was affected by the German occupation.
Surviving HDA motorcycles can have complicated histories because many were later sold as surplus, civilianized, restored, or rebuilt using parts from other Terrot models. Frame and engine numbers, military markings, registration documents, period photographs, original equipment, and restoration records are therefore especially valuable when establishing provenance.
The 1938 Terrot HDA 350 is powered by a 350 cc single-cylinder four-stroke side-valve engine.
The side-valve configuration emphasizes simplicity, durability, and ease of maintenance rather than high specific output.
The engine is air-cooled and uses a period carburetor and magneto ignition system.
The 350 cc displacement provides useful low-speed torque and was well suited to the HDA's military utility role.
Published technical references give the HDA a top speed of approximately 85 km/h, with output around 9.5 horsepower at approximately 3,800 rpm. These figures are consistent with the motorcycle's utility-oriented design rather than a sporting specification.
Actual performance depends heavily on engine condition, compression, carburetion, ignition timing, valve condition, exhaust system, gearing, and restoration quality.
The HDA uses a three-speed manual gearbox with a hand-operated gear-change arrangement.
The three-speed transmission was appropriate for the motorcycle's intended military and utility use and provided a simple, durable drivetrain.
Power is transmitted to the rear wheel through a conventional chain final drive.
The clutch, gearbox, primary drive, chain, sprockets, bearings, and rear hub should all be inspected carefully on a surviving HDA.
The hand gear-change mechanism is an important feature when assessing authenticity, particularly because surviving motorcycles may have been converted or modified for civilian use.
The 1938 Terrot HDA uses a conventional tubular steel motorcycle frame.
The chassis was designed primarily for durability and practical military service rather than maximum sporting performance.
The front suspension uses a period parallelogram or girder-style fork, while the rear of the motorcycle uses a rigid frame without modern rear suspension.
This combination was common among utility motorcycles of the late 1930s and provided a relatively simple and robust chassis.
The frame, steering head, fork pivots, engine mounting points, rear wheel alignment, and frame tubes should be carefully inspected for cracks, distortion, corrosion, or previous repairs.
Military motorcycles were often used in demanding conditions, so evidence of field repairs or later civilian modifications is not unusual.
The HDA 350 uses wire-spoked wheels with mechanical drum brakes at both ends.
Available specifications identify approximately 170 mm brake dimensions for both the front and rear brakes.
The braking system was designed around the motorcycle's modest performance and military utility role.
Brake drums, shoes, operating mechanisms, cables, wheel bearings, spokes, rims, and tires should all be inspected before riding.
Original Terrot hubs and period brake components are useful indicators when assessing the authenticity of a restored military HDA.
The 1938 Terrot HDA uses period French motorcycle electrical and ignition equipment.
Magneto ignition provided the single-cylinder engine with an independent source of ignition, an important feature for military service where reliability and simplicity were essential.
Military examples could be equipped with lighting and electrical equipment appropriate to service requirements.
The magneto, generator, wiring, headlamp, switches, horn, rear lamp, and other electrical components should be examined for both operation and historical correctness.
Many surviving HDA motorcycles have received replacement wiring, rebuilt magnetos, modern regulators, or other electrical upgrades during civilian restoration.
The 1938 Terrot HDA has the purposeful appearance of a French military utility motorcycle from the late 1930s.
The exposed 350 cc side-valve engine, substantial fuel tank, tubular frame, rigid rear chassis, wire wheels, military equipment, and upright riding position create a practical rather than purely sporting appearance.
The HDA was based closely on the civilian HD, but military equipment and specification gave it a more utilitarian character.
Correct military tank markings, frame finish, controls, exhaust, mudguards, tool equipment, electrical components, and period hardware are important when restoring an HDA.
The 1938 model year is particularly important for the Terrot HDA because it represents the beginning of the model's documented military production period.
Terrot's 350 cc range at this time included several civilian and sporting models, while the HDA served the military market as a utility version of the HD.
The contemporary Terrot model range identifies the civilian HD as a 350 cc side-valve motorcycle and the HDA as its military derivative.
The HDA was intended to provide reliable transportation for military personnel and equipment under conditions where mechanical simplicity and durability were more important than outright speed.
The motorcycle therefore represents the growing importance of military contracts to the French motorcycle industry immediately before the Second World War.
The Terrot HDA 350 has the characteristic riding behavior of a large side-valve single-cylinder motorcycle.
The engine delivers useful torque at relatively low engine speeds and is designed for steady, dependable operation rather than high-revving performance.
The three-speed gearbox and hand gear change emphasize the motorcycle's utility character.
The rigid rear frame and period front fork provide a distinctly vintage ride compared with later motorcycles equipped with full suspension.
The HDA is best suited to moderate-speed riding, historical events, military motorcycle displays, and carefully conducted touring on suitable roads.
A surviving example should be operated conservatively until the engine, lubrication system, carburetor, magneto, clutch, gearbox, steering, fork, wheels, tires, and brakes have been thoroughly inspected.
The 1938 Terrot HDA 350 is historically important because it represents Terrot's response to the growing demand for military motorcycles immediately before the Second World War.
The motorcycle demonstrates how an established civilian design could be adapted for military service while retaining a simple and dependable mechanical specification.
The 350 cc side-valve engine, three-speed gearbox, rigid rear chassis, and mechanical drum brakes were all well suited to military utility work.
The HDA also forms part of the broader history of French motorcycle manufacturers supplying machines to the armed forces during the late 1930s.
Terrot subsequently became heavily involved in wartime production, making surviving pre-war military HDA motorcycles particularly interesting historical artifacts.
The 1938 Terrot Model HDA 350 is an appealing motorcycle for collectors specializing in French, military, and pre-war motorcycles.
Its military specification, 350 cc side-valve engine, relatively simple chassis, and connection with Terrot's civilian HD make it an important representative of French utility motorcycle design.
Collectors should pay close attention to the engine, cylinder and valve-side components, crankcases, carburetor, magneto, gearbox, hand-shift mechanism, frame, fuel tank, fork, wheels, brakes, exhaust, military equipment, and electrical components.
Frame and engine numbers are especially important because military motorcycles were often rebuilt, renumbered, civilianized, or fitted with replacement parts after leaving military service.
Original military equipment, period markings, correct Terrot components, original finishes, service documentation, and documented provenance can substantially increase historical significance.
Authenticating a 1938 Terrot HDA 350 requires examination of the complete motorcycle rather than relying solely on its engine.
The engine should be identified through its crankcase castings, cylinder, side-valve arrangement, carburetor, magneto, and period details.
The frame should be inspected for its correct tubular construction, steering head, engine mounting points, rear section, and frame-number markings.
The three-speed gearbox and hand-operated gear-change mechanism should be checked because these features are important to the HDA's period specification.
The military equipment, fuel tank, mudguards, wheels, brakes, exhaust, headlamp, controls, and electrical system should be compared with period photographs and Terrot documentation whenever possible.
Engine and frame numbers should be recorded and preserved as part of the motorcycle's historical documentation.
Military registration documents, unit markings, period photographs, French Army records, restoration invoices, and previous ownership documentation can provide valuable evidence of provenance.
The 1938 Terrot Model HDA 350 matters because it represents one of Terrot's pre-war military motorcycles and provides an important connection between civilian French motorcycle engineering and military transportation.
Its 350 cc side-valve single-cylinder engine, three-speed gearbox, rigid rear chassis, parallelogram front fork, and military specification reflect the practical engineering priorities of the late 1930s.
The HDA also illustrates the growing role of French motorcycle manufacturers in military supply during the period immediately preceding the Second World War.
For collectors, an authentic HDA with original military equipment and documented history can be significantly more interesting than a civilianized example.
A well-preserved or accurately restored 1938 Terrot Model HDA 350 with its correct engine, chassis, military equipment, period finishes, and documented provenance represents a significant example of French pre-war motorcycle history.
This 1938 Terrot Model HDA 350 represents an important example of French military motorcycle engineering immediately before the Second World War.
Its 350 cc single-cylinder side-valve engine, three-speed hand-change gearbox, robust tubular chassis, parallelogram front fork, rigid rear frame, and military specification give it a distinctive historical character.
The HDA was the military derivative of Terrot's 350 cc HD and was produced for military service during the late 1930s. Contemporary Terrot model references identify the HDA as a military 350 cc model covering approximately 1938 to 1940.
For collectors, the correct HDA engine and chassis, original military equipment, period fuel tank and markings, hand-shift gearbox, wheels, brakes, lighting equipment, and documented military provenance are particularly important when establishing authenticity.
A well-preserved or accurately restored 1938 Terrot Model HDA 350 with correct period components and strong documentation represents a significant piece of French motorcycle and military history.
Contact us for additional photographs, detailed specifications, engine and frame numbers, service history, originality assessment, restoration information, historical documentation, and purchasing information for this 1938 Terrot Model HDA 350.
The Vintage Motorcycles presents a curated selection of historically significant French vintage motorcycles, with a dedicated focus on Terrot Motorcycles, a manufacturer that illustrates the transition of French industry from artisanal bicycle production to structured, large-scale motorcycle engineering. Founded in Dijon in the late 19th century, Terrot developed machines that balanced accessibility, mechanical simplicity, and industrial efficiency - qualities that made them representative of everyday mobility in early 20th-century France.
This collection is contextualized within the broader ecosystem of global motorcycle history, where you can explore additional manufacturers through our global vintage motorcycle brands archive. Within the French engineering landscape, Terrot occupies a position that reflects the expansion of motorcycle use beyond experimentation into practical transportation. Its machines embody a pragmatic design philosophy shaped by real-world road conditions and the growing demand for reliable, affordable mobility. These developments are best understood within the framework of pre-war motorcycle engineering (1900-1939), where industrial standardization began to emerge from a previously diverse and experimental field.
Each motorcycle within our collection is carefully selected based on provenance, originality, and mechanical integrity, ensuring alignment with museum-grade preservation standards. Available machines can be explored through our global vintage motorcycle inventory, including lightweight Terrot commuter models and more structurally adaptable configurations such as those found in our sidecar motorcycle collection, which demonstrate the versatility of French engineering across both civilian and utility applications. All acquisitions are supported by a fully insured international shipping service designed for global collectors.
French engineering in the early 20th century developed through a balance of innovation and practicality, and Terrot serves as a representative example of this equilibrium. Rather than focusing on extreme performance or experimental configurations, Terrot prioritized mechanical clarity, ease of maintenance, and adaptability to everyday use. This approach aligned with the broader needs of a rapidly modernizing society, where motorcycles increasingly functioned as accessible transportation rather than purely experimental machines.
This evolution becomes clearer when examined through broader historical transitions. During the formative period documented in pre-war motorcycle development, Terrot contributed to the gradual stabilization of motorcycle design, moving from varied and often improvised configurations toward more consistent mechanical standards. As industrial priorities shifted during global conflict, motorcycle engineering adapted to new demands, as reflected in wartime motorcycle engineering, where durability, simplicity, and reliability became central design principles.
In the post-war period, Terrot - like many European manufacturers - operated within an increasingly standardized and competitive industrial environment. This transition is further explored in post-war motorcycle development, where mass production, economic accessibility, and functional efficiency shaped the next phase of engineering evolution. Within this broader continuum, Terrot remains an important reference point for understanding how French manufacturers translated engineering principles into practical mobility solutions that defined everyday transportation across Europe.
Key Highlights
Collector Assurance
All enquiries handled with discretion. We typically respond within 6 hours.
Choose the payment method that is most convenient for you. We accept widely used international payment methods as well as, where available, local bank transfer options that allow you to pay like a domestic transaction. Full payment instructions are provided for your specific purchase.
Direct international bank wire transfer is available for motorcycle purchases and export transactions.
Credit card payments can be arranged through Wise.com, subject to the applicable payment and processing conditions.
PayPal is accepted. A 5% PayPal processing fee applies to the transaction.