Motorcycle PMZ-A-750: technical specifications
The production of motorcycles began to emerge in the USSR a few years after the end of the Civil War. In the early years of the USSR, a number of factories carried out overhaul and refurbishment of motorcycles and cars. The first steps to create their own production of motorcycles were taken closer to the mid-20s.
The first steps of the USSR motorcycle industry
At the very end of 1924, the former Dux factory (in those years it was called Plant No. 1 of OCOAviaKhim) in Samara was made and assembled a motorcycle sample.
Motorcycle and engine were the original design. But at the same time they contained a lot of decisions borrowed from various foreign motorcycle manufacturers. The four-stroke engine developed about 10 horsepower and had one cylinder. The gas distribution mechanism had an exhaust valve with a lower location and driven by a camshaft. The exhaust valve was in the non-removable cylinder head and worked from the vacuum in the cylinder that occurs when the piston moves down.
The motorcycle took part successfully in the test run, but it did not come to mass production.
The first motorcycles IL
Another center for the development of motorcycle production was the Izhevsk Mechanical Plant. It was in Izhevsk that the design office was formed under the direction of Pyotr Vladimirovich Mozharov, thanks to many of whose work the motorcycle industry originated in the USSR.
The main products of the Izhevsk plant in those years were small arms — the Maxim machine guns and Mosin rifles. The high-precision equipment available at the factory and high production culture were well suited for the manufacture of motorcycle parts. KB Mozharova created several types of motorcycles. Some of them had purchased engines (the German company Wanderer), and a few were equipped with engines of their own design.
The high workload of the factory with army orders did not allow the serial production of any of these machines. A few years later, in Izhevsk, they nevertheless began to assemble a motorcycle IL-7, which was a copy of the motorcycle of the German company DKV. Works on adapting the design of the motorcycle under the conditions of production in the USSR were conducted by the same P. V. Mozharov.
Prerequisites for the creation of PMZ-A-750
Mastering the production of motorcycles IZH-7 and L-300 of identical design (produced at the Red October plant in Leningrad) made it possible to begin their deliveries to the army. But these cars were light, and armies needed heavy motorcycles that could be operated with a side trailer.
The starting point for the creation of a heavy motorcycle became the machines of the American firm Harley Davidson (Harley & Davidson). Motorcycles of this brand were supplied to the USSR in sufficiently large volumes and showed themselves well.
Development of NATI-A-750
The decision to create a motorcycle was made by a decision of the Council of National Economy in the autumn of 1931. In accordance with the decree, work began on designing a motorcycle with a two-cylinder engine and a working volume of 750 cubic centimeters.
The works took about a year and were conducted at NATI in a separate Motorcycle Building Design Bureau under the supervision of P. V. Mozharov. In addition to Mozharova, many talented designers worked in the bureau, such as I. Okunev and B. Fitterman, who would later become the leading designers of automobiles in the USSR. The new model received the NATI-A-750 index,where the letter "A" denotes the possibility of operating the machine with a side trailer (only on paved roads), and the numbers indicate the rounded working volume of the cylinders.
The manufacture and assembly of the first samples of NATI-A-750 motorcycles was carried out at the end of 1932 in Izhevsk. Trial tests of the engines showed their performance and gave indications of power from 16 to 18 forces, which corresponded to the initial task and calculations. In the spring of next year, motorcycles successfully passed the test run from Izhevsk to Moscow.
However, soon a new decree was issued - on the development of the Izhevsk IL-7 production in Izhevsk and on the transfer of the NATI-A-750 production to Podolsk
The appearance of the designation PMZ-A-750
For the production of motorcycles, areas of the Podolsk Mechanical Plant (PMZ) were allocated, which for many years carried out the production of sewing machines, simultaneously performing various military orders. P. V. Mozharova was again appointed to organize the production at a new place.
Mastering the production went with great difficulty, because the plant did not have the necessary equipment, technology and qualified staff. As a result, P. Mozharov never saw the mass production of his brainchild - in the spring of 1934 he committed suicide.
In the summer of 1934, the PMZ-A-750 motorcycles were shown to the People's Commissar S.Ordzhonikidze, who approved the design and demanded the speedy start of large-scale production. It was established from the next year and lasted four years. During this time, more than 4,630 motorcycles were collected.
Motorcycle PMZ-A-750 was supplied to the army, various government agencies (police, NKVD) and was sold to private hands. The maximum speed of the motorcycle reached 90 km / h with an average consumption of about 6 liters of low-octane A56 gasoline per 100 km. The motorcycle had a strong, but unfinished design. Especially a lot of complaints were caused by the engine ignition system, it was not for nothing that one of the comic decodes of PMZ was the phrase “Try me to start it”. Another defect was the resonance of the front fork at speeds of about 40 km / h. After the death of P. V. Mozharov, the design was practically not refined. In addition, in the USSR, work began on the creation of more advanced machines, which led to the creation of the famous M-72.
These facts caused the termination of the release of the motorcycle in 1939. Podolsky plant never returned to the assembly of motorcycles.
Structurally, the motorcycle was a mixture of solutions of the German and American motorcycle schools. The frame and chassis were created with an eye on the German motorcycles BMW.The duplex frame was assembled from two trusses from separate stamped elements.
The gas tank for PMZ-A-750 with a capacity of about 21 liters was located between the farms of the front part of the frame. The front fork of stamped profiles was equipped with an 8-leaf spring, which partly softened the bumps from road irregularities. The rear wheel did not have a suspension and was rigidly attached to the frame.
The four-stroke engine was almost a complete replica of Harley-Davidson products. Motorcycle PMZ-A-750 had two cylinders arranged V-shaped. The power of serial motors did not exceed 15 forces. Engine start foot, using the pedal. The gas distribution system was driven by gears.
In one crankcase with a motor housed a three-speed gearbox. The torque from the engine to the box was transmitted through a multi-plate clutch. The engine was equipped with a dry sump circulating lubrication system (powered from a separate 2.25 liter oil tank) and a 6 volt battery ignition system. The ignition system included a generator, a coil and a distributor. Drive rear wheel chain.
Both wheels of the motorcycle had drum brakes, driven by a pedal (rear drum) and from a lever on the steering wheel (front drum).
The motorcycle could work with a side carriage.The stroller had a welded frame and was attached to the frame of the motorcycle with the help of three ball joints. The carriage body with one passenger seat made of steel sheet was suspended to the frame on two leaf springs.