Some PANNONIA Motorcycle Owner's Manuals PDF above the page - 250, T5.
Pannonia is a brand of motorcycles manufactured by the Hungarian Csepel plant from 1956 to 1975.
Initially (1956 - 1957), engine power did not exceed 10 hp. with a compression ratio of 6.5.
In 1958, due to a change in the size of the windows in the cylinder, a slightly different shape of the inlet channel and an increase in the compression ratio to 6.8, the power increased to 12 hp. at 4500 rpm
Many improvements appeared in the design of the motorcycle in 1959-1960. A double seat cushion, reinforced spokes, a double-acting shock absorber in the rear wheel suspension were introduced, the volume of the fuel tank was increased from 16 to 18 liters.
As for the engine, instead of the carburetor of the previous design with a separate float chamber, it began to be equipped with a new one, such as a monoblock, in which the diameter of the mixing chamber became larger (27 mm instead of 25).
The transition to a new carburetor and an increase in the compression ratio to 7.2 affected the power: it increased to 14 hp. at 5100 rpm
The use of a DC generator on parts of machines also refers to the same period.
In the mid-1950s, cylinders with vertical slots in the ribs were introduced to compensate for thermal deformations, modified taillights and muffler tips.
Then, from 1961 on Pannonia candle tips with suppressors of radio interference began to be used, and since 1962, the bronze bushing of the piston pin gave way to the ceramic-metal one.
By the beginning of the 1970s, despite its unconditional merits, Pannonia was outdated. The plant did not want to focus, like Jawa, only on the Soviet market, which took the bulk of its products.
Therefore, it acquired a license for the Japanese Yamaha-IDS2 model and began its release as the Pannonia P20. This motorcycle was more complicated and more expensive than its predecessor.
The company’s revival project began in 2007 and 4 years later came to fruition.