M-72
Dnepr M-72 in Motor of War museum
The M-72 is a Soviet heavy motorcycle based on the German BMW R71.
This motorcycle was produced in large quantities from 1941 to 1960 at many factories: MMZ in Moscow, “Serp i Molot” in Kharkov, GMZ in Nizhny Novgorod, IMZ in Irbit, “Krasny Oktyabr” in St. Petersburg, KMZ in Kiev and “Zavod im. Lepse” in Kirov.
The motorcycle was initially intended for military purposes and was not available for free purchase until the mid-1950s.
Each M-72 was equipped with small arms, so according to the classification of the Main Artillery Directorate of the Red Army it belonged to the category of “armored vehicles”. In total, more than 330,000 units of this motorcycle were produced, of which 16,860 were produced during the Great Patriotic War. It was produced both with a sidecar and in a single version.
M-72 in the FSO Museum (VDNKh, Moscow, Russia)
History
In early 1940, the USSR decided to create a special army motorcycle. The project was headed by N. P. Serdyukov, who had been an intern at the BMW plant in Germany from 1935 to 1940. A specialized design bureau for the development of heavy motorcycles was created on the basis of the Moscow experimental plant “Iskra”. The BMW R 71 (BMW-750) motorcycle, which had proven itself well in the Wehrmacht by that time, was chosen as a model for complete copying.
Five motorcycles were purchased in Sweden without specifying the manufacturer. Since the spring of 1941, serial production of the motorcycle under the M-72 brand began at the Moscow Motorcycle Plant (MMZ). As part of the cooperation, ZIS developed technical documentation and supplied engines, KIM (now AZLK) – gearboxes, and GAZ – a cardan shaft and sidecar.
The Moscow Motorcycle Plant continued to produce motorcycles until 1951. In addition, production was established at the Kharkov plant, which was supplied with engines from the Kiev plant of medical instruments. In Leningrad, the production of the M-72 was also entrusted to the Krasny Oktyabr plant.
From February 25, 1942, the production of M-72 motorcycles was evacuated to Irbit, where equipment from the MMZ, KiM, ATE-1 and the ZiS engine shop was taken. The main design bureau also moved from Moscow to Irbit. It was headed by Alexander Minovich Fedorov, and among the designers were I. I. Okunev, N. A. Kukin, V. V. Bekman and testers S. I. Karzinkin and B. V. Zefirov.
At the same time, in parallel with the Irbit Motorcycle Plant (IMZ), the Gorky Motorcycle Plant (GMZ), previously known as “Red Etna”, began producing M-72 motorcycles.
Since 1951, the Kiev Motorcycle Plant (KMZ) also mastered the production of M-72, which subsequently began to develop its own design. Interestingly, there were no differences in the design (or even in the emblems) between the M-72 motorcycles produced by the Moscow, Irbit, Leningrad, Kharkov and Gorky plants.
Since 1955, M-72 motorcycles have become available to the general public. The civilian version of the IMZ plant was distinguished by an improved engine, reinforced wheels and frame, torsion bar suspension of the sidecar wheels, a new color scheme and the inscription “Irbit” on the tank. However, all these civilian motorcycles were registered with the military registration and enlistment office and were subject to requisition in case of war. A total of 8.5 thousand of these motorcycles were produced.
Design
The design of the prototype, the BMW R71, was intended for mass production and included many technical solutions that had not previously been used in Soviet motorcycles. Among them were a duplex frame, foot-operated gear shifting, spring suspension of the rear wheel, telescopic front fork (in the last series of the M-72 after the war, a lever fork was installed), cardan transmission and power supply for each cylinder from a separate carburetor.
The opposite arrangement of the cylinders in the engine not only ensured its excellent balance, but also allowed for a low center of gravity of the entire motorcycle. In the M-72 model, it was located at a height of 592 mm.
All auxiliary units, such as the breaker, oil pump and generator, were driven by gears. The cast iron cylinders were covered with heat-resistant black varnish, which protected them from corrosion. The crankshaft bearings were made of different materials: the connecting rod bearings were made of roller bearings, and the main bearings were made of ball bearings.
The connecting rods were not located on a common journal, but on individual ones, which ensured better engine balancing. Because of this, the left cylinder was shifted forward relative to the right by 39.2 mm.
To reduce the length of the engine crankcase and, consequently, its weight (with the gearbox, it weighed 75 kg), the crankshaft on the M-72 was made according to the prototype (R71) with two supports.
Among its contemporaries, the M-72 motorcycle stood out for its unique control levers, the ends of which were directed not outward, but inward. This minimized the risk of damage during falls.
The motorcycle was equipped with bags for ammunition and spare parts, as well as special brackets with a rotating device for a light machine gun (swivel). The Degtyaryov machine gun was attached to the swivel plate, which significantly facilitated its transportation and allowed it to fire both from a stationary position and on the move.
In limited quantities, the troops also received modifications where an 82-mm mortar was installed instead of the sidecar body.
In 1949, a dual air filter was installed on motorcycles: mesh and inertial-oil. Since 1950, a new device RR-31 began to be used instead of the RR-1 relay regulator.
In 1952, an improved G11A generator was developed and introduced. Its power remained unchanged for both the previous G11 model and the subsequent G414.
Since 1956, IMZ began producing the M-72M model. The main innovation was a change in the engine design: a ball bearing was installed instead of the front bearing sleeve of the camshaft. This change occurred back in 1955.
To avoid blocking the wheels with sticky mud, the front shield was raised and secured to the sprung part of the front fork. In addition, the motorcycle received a new sidecar.
There was no further development of the M-72M, as IMZ switched to the M-61 model with an overhead valve engine.
Sports modifications
- The M-72K is a motocross motorcycle designed for sports clubs, produced in limited quantities. It features a lightweight design and a forced engine with a power of 30 hp. The increase in power was achieved by changing the valve timing, increasing the valve lift height and additional processing of the intake and exhaust ports.
- The M-75M is a sports motorcycle with a sidecar based on the road M-72. The engine has overhead valve heads made of aluminum alloy, hemispherical combustion chambers, rocker arms with needle bearings.
- The M-76 is a sports motorcycle for solo riding, created on the basis of the road M-72. Its engine and gearbox are the same as the M-75M, but there is one important feature – a dry sump lubrication system. The oil tank is located near the seat, and the ignition is carried out using a magneto.
- The M-80 is a racing motorcycle that was developed at the Gorky Motorcycle Plant (GMZ) in 1946 based on the road M-72. It is believed that engineer Naum Gudkin, the creator of the motorcycle, used the developments on the M-75 engines, which were being developed at the same time. This was possible thanks to the centralized industrial system in the USSR, which allowed the transfer of parts and entire structures between enterprises. In 1947, Honored Master of Sports of the USSR Evgeny Gringaut set an all-Union speed record on this motorcycle in the class up to 750 cm³ – 170 km/h.
Manufacturer:
- ММЗ (Дукс) (Московский машиностроительный завод «Коммунар»)
- Серп и молот
- ГМЗ (Горьковский мотоциклетный завод)
- ИМЗ (Ирбитский мотоциклетный завод)
- «Красный Октябрь»
- КМЗ (Киевский мотоциклетный завод)
Assembly: Moscow / Kharkov / Gorky / Irbit / Leningrad / Kiev (USSR)
Years of production: 1941—1960
Production: +330,000 units
Length: 2130 mm
Width: 815 mm
Height: 960 mm
Engine: 2 cylinders; 746 cc
Power: 22 HP
Max speed: 110 km/h
Fuel consumption: 7 l/100 km
Weight: 219 kg
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