Harley-Davidson Model U / UL classic motorcycles for sale

History of the Harley-Davidson Model U / UL

Harley-Davidson introduced the Model U series in 1937 as an answer to the growing demand for heavy-duty, reliable touring motorcycles. Conceived as a successor to the Model V, the Model U featured the all-new 74 cubic inch (1207cc) sidevalve V-twin engine. This powerplant was noted for its quiet, smooth operation and legendary durability, contributing significantly to Harley’s reputation for ruggedness. The Model UL ('L' for high-compression) expanded the range by offering higher compression and improved performance for riders seeking more power. These motorcycles witnessed extensive use by both civilians and military forces during the turbulent years leading up to and following the Second World War.

Model history and evolution

The Model U series evolved directly from Harley’s earlier Model V bikes, continuing the tradition of sidevalve V-twin engines. The Model U marked Harley’s last major sidevalve development for big twins, as the introduction of the knucklehead OHV engine in 1936 shifted the industry focus. Production of the Model U and UL continued well into the late 1940s, after which the range was slowly phased out in favour of the more modern OHV-powered models. The U and UL models are thus often considered the final, mature expression of Harley's commitment to the sidevalve motor in large-displacement motorcycles.

Highlights and unique features

Distinctive for their sidevalve 74” engines, the Model U/UL motorcycles also feature aluminium cylinder heads (on the UL variant), a rigid frame, and their unique teardrop fuel tanks. Their design is instantly recognisable due to deeply valanced fenders and classic hand-shifter and foot clutch arrangement. Many enthusiasts value the Model U and UL for their exceptional mechanical simplicity, torque-rich engine character and classic lines, which reflect Harley-Davidson's pre-war identity.

Technical data

Special editions and limited models

While the U and UL were the primary offerings, Harley-Davidson produced several military derivatives of the Model U configuration during WWII, often identified by specialised equipment such as blackout lighting and luggage racks. Additionally, rare factory paint schemes and dealer-specific customisations—such as two-tone tanks or unique badging—can sometimes be found on surviving examples, adding intrigue for collectors.

Engine, performance, transmission and handling

Riding a Harley-Davidson Model U or UL is characterised by abundant low-end torque and a relaxed V-twin exhaust note, the hallmark of sidevalve engineering. Performance is best described as smooth but not brisk; acceleration is adequate for the era, but these machines favour long-distance cruising over high-speed antics. Gear changes demand a deliberate hand-shift technique paired with foot clutch operation, reinforcing the vintage character. The suspension is basic, dominated by a rigid frame and leading-link springer fork, so ride quality is firm and road communication is direct. Braking performance relies on period drum brakes, which require anticipation and good mechanical condition for optimal results. - Harley-Davidson Model U: 74cu in sidevalve V-twin, three-speed, approx. 27hp.

• Harley-Davidson Model UL: High-compression version, subtle performance improvements due to revised cylinder head and higher compression ratio.

Design, interior, comfort, exterior and accessories

The Model U/UL motorcycles are period pieces, featuring deeply valanced fenders, teardrop tanks with chromed accents, classic Harley script logos, and a rigid rear frame. The cockpit is spartan with a solo sprung saddle, minimal instrumentation, and handlebar controls typical of 1930s and 1940s motorcycles. Popular options included springer front forks, luggage carriers, toolboxes, and distinctive horn and lighting designs. Paint schemes ranged from single factory colours to occasional two-tone variants with period pinstriping, particularly for civilian models.

Other notable features

Some Model U and UL motorcycles came equipped with sidecars or special police equipment, often making them preferred workhorses for law enforcement and utility services. Their robustness, ease of maintenance, and parts interchangeability with other period Harleys contribute to their long-term survival and continued road use.

Summary

The Harley-Davidson Model U and UL series epitomise the final generation of large sidevalve V-twin motorcycles from Milwaukee, marking a transitional bridge between pre-war and post-war Harley engineering. Their mechanical honesty, distinctive ride experience, and unmistakable styling secure their significance among classic motorcycle collectors and riders who value authentic American motorcycling heritage.