M-72 from the «Motorworld by V.Sheynov» collection
Irbit Motorworks built the first test M-52 in 1954. Its engine was designed by the Central design bureau. Let’s take a look at the Central design bureau’s official report: “Engine is based on an M-72 engine for maximum compatibility with spare parts; a mass produced crankcase having some minor modifications made at the last production stages is used. Diameters of the crankshaft necks & piston pins, piston rollers and separators are all unified with corresponding parts used in M-72. Valve train, which is taken from proven hardware, is almost similar to one used in BMW R-51/3; additionally, it has some technological advantages. Aluminium-cast cylinders has cast-iron liners…”.
Manufacturing of M-52S, a road racing model, has started in 1957. This machine had an M-77 chassis; the front fork was equipped with an M-52 wheel axle displaced forward. The engine was an upgraded mass produced M-52 engine. As for the speed performance, the bike was equal to the legendary BMW R37 that considered one of the best motorcycles during 1930s and after the WWII.
M-52S engine had an unique valve cover with three longitudinal stringers. By using the compression ratio 9.0 and twin carburettor configuration, the engine capacity increased to 35 h.p. at 6,200 rpm, which speeded the machine up to 160 km/h. In addition, high octane fuel had an impact on speed.
From 1957 till 1961, 20 machines were manufactured and every M-52S was hand assembled.
|Manufacturer||Irbit Motorcycle Plant, Irbit, USSR|
|Years of manufacture||1957-1961|
|Quantity produced, units||20|
|ENGINE AND TRANSMISSION|
|Engine capacity, cc||494|
|Bore and stroke, mm||68 х 68|
|Engine rating||35 hp at 6200 rpm|
|Carburetor||К-93 for each cylinder|
|Clutch||Dry double plate|
|FRAME AND WHEELBASE|
|Frame type||Duplex tubular|
|Front suspension||Spring-mounted, with hydraulic shock absorber|
|Rear suspension||Candle-type spring-mounted, with no shock absorber|
|Wheel size||3,50 х 19|
|Ground clearance, mm||
|Seat height, mm||
|Gas tank size, l||
|Maximum speed, km/h||