Horex Imperator
| Horex | |
|---|---|
|
|
| Emperor | |
| Manufacturer | Horex-Werke KG |
| Production period | 1955 to 1957 |
| class | motorcycle |
| design type | Naked bike |
| Motor data | |
| 2-cylinder four-stroke, OHC | |
|
|
| transmission | 4-speed |
| drive | Chain |
| Brakes | Full-hub simplex drum brakes |
| Wheelbase (mm) | 1400/1380 |
| Empty weight (kg) | about 195 |
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The Horex Imperator was the only mass-produced motorcycle with a two-cylinder four-stroke engine and OHC valve control that the Horex-Werke KG , Fritz Kleemann , built in Bad Homburg after the war. The parallel two-cylinder with an overhead camshaft was developed under the direction of chief engineer Hermann Reeb, who had already developed the engines of the S 6 and S 8 models with 600 cm³ and 800 cm³ in the 1930s. The prototype of the Horex Imperator with a 500 cm³ engine was presented at IFMA 1951. Series production with a 400 cm³ engine began in 1955; After about two years, the production of the Imperator ended, last built in cooperation with Zündapp as the Zündapp Citation for the American market. It is estimated that around 4,000 Horex Imperator were built.
Development history and technology
The motorcycle boom in Germany peaked in 1952; In the fall of 1951, Horex presented the two-cylinder model Imperator alongside the Horex Regina . Around 20,400 Reginas were sold in 1952, but by 1953 there were only 17,500 and by 1955 the number had dropped to 7,000. The Imperator and the successor to the Regina, the single-cylinder Resident, should stop this development. In the catalog 100 Motorcycles in Words and Pictures from 1952 the price of the Imperator was given as 2,850 DM.
Prototype of the Emperor
Unlike the Regina, a further development of the pre-war model SB 35, the Imperator was a new design.
The engine of the prototype as well as the later series model was a wind-cooled parallel twin with synchronous pistons and an overhead camshaft that controlled the valves via rocker arms. The cylinders were made of gray cast iron , the separate cylinder heads made of aluminum. A novelty patented for Horex in 1949 was the arrangement of the chain for driving the camshaft in a light metal housing between the cylinders. In a press release from the manufacturer, it said: "In addition to its originality, this chain guide has an absolute symmetry in the external structure of the engine and, compared to the previously external timing drive, now allows easy access to the spark plugs and thermal balance." The 500 cm³ -Motor made 30 hp at 6800 revolutions per minute. The top speed was 150 kilometers per hour.
The gearbox was integrated into the motor housing (so-called block motor ). The press release emphasized that the gear or primary chain can be adjusted from the outside. As a “further novelty” it was pointed out that there is “a small step lens” (push button) above the footshift lever on the left of the four-speed gearbox, in order to switch directly to neutral from any gear. The gearbox was manufactured by Hurth Getriebe und Zahnräder in Munich.
The chassis of the Imperator consisted of a double tube frame , telescopic fork and rear swing arm with 80 millimeters of spring travel. The fork and swing arm were hydraulically dampened. The front and rear wheels had thru axles. A fairing of the rear wheel area should improve the streamlining and avoid dirty corners. The encapsulated battery underneath was accessible through a flap. To remove the panel, only a few screws had to be loosened.
At the same time as the Imperator, the development of a 500cc Horex factory racing machine took place, which apparently overstrained the capabilities of the test department, so that the initially extensive test drives with the Imperator prototypes and the work to improve series production were stopped. Outwardly it was said that such a powerful motorcycle as the Imperator was unsuitable for normal riders and could only be mastered by top athletes.
Series-built Horex Imperator
At the beginning of 1954, the Imperator project was taken up again and the new motorcycle was ready for series production in less than six months. As early as December 1954, Horex presented the first ready-to-drive machine, which differed from the prototypes in various ways. The engine and frame were new designs. Production started in 1955.
In consideration of the then usual taxation and insurance of motorcycles according to the displacement instead of performance, the displacement was reduced from the original 500 cm³ to 400 cm³, contrary to the recommendation of chief engineer Rudolf Gunkel. In a press release it said: “With its 26 HP continuous load high-performance motor and a cruising speed of 135 km / h, it [the Imperator] belongs to the international top class of 500 models. For the buyer this means: the tax payment of a 350, the economy of the medium-heavy class and the performance of the really big ones. "
The engine was offered with either one or two carburetors. With a carburetor, the maximum output was 26 HP at 6500 / min, the continuous output was 24 HP at 5650 / min. With two carburettors the maximum output was 27.8 HP at 7350 rpm, the continuous output 26 HP at 6200 rpm. Instead of a three-part motor housing, the series model has a two-part, vertically divided motor housing made of light metal. The original individual cylinders and the cylinder head are cast together as a unit. To transmit power from the engine to the gearbox ( primary drive ), the originally intended chain has been replaced by helical gears. The roller chain (5/6 × 1/4 ″) was retained for the secondary drive from the gearbox to the rear wheel. It is protected against dust and dirt by an oscillating chain case. For lubrication, the chain runs over lubricating felts riveted into the chain case.
The production model also has a closed double tubular frame. As an alternative to the oil-damped telescopic fork, after a short construction period there was a front swing arm with also oil-dampened spring struts, which was mainly recommended for use with a trailer. As from the beginning, the rear wheel is guided in a swing arm; their suspension struts are adjustable in order to adapt them to the different loads of solo or pillion rider or with a sidecar. There is no fairing for the rear wheel area on the production model. Below the double seat bench there is a box on the left and right that can hold tools and any other small parts; Another small storage compartment, in which the air pump is located, is under the fold-up bench.
Trailer operation
The Imperator is prepared for carriage operation. In order to drive with a sidecar, the solo transmission must be exchanged for a sidecar transmission, i.e. both the small gear ( pinion ) on the gearbox and the gear on the rear wheel must be replaced. There are 13 instead of 14 teeth on the gearbox, and 43 instead of 41 teeth on the rear. In the operating instructions it is pointed out and shown in a sketch that a toe-in of 25–30 millimeters must be set, which can be adjusted on the lower struts of the sidecar. Before the sidecar is firmly connected, make sure that its floor is horizontal and that the motorcycle is vertical in an unloaded state. The rear wheel of the motorcycle must have tires with 4.00–18 when used in a trailer; the sidecar wheel has a tire size of 3.25–18. The maximum speed of the combination is 115 kilometers per hour with a two-carburetor engine.
Variants of the Imperator
In addition to the standard version of the Imperator, Horex offered variants for sports drivers. The advertising said: "When and where you start, whether on the road or off-road, whether in reliability drives or in races, Horex will help you with custom-made off-road and supersport models." These models with the additions RS (racing) or GS (Off-road sports) made up to 37 hp and were up to 170 km / h fast.
The Imperator could not stop the decline in sales at Horex and in the motorcycle industry in general. In 1957 the sales price was reduced by DM 200 from DM 2,585, but this did not bring the hoped-for success. The last variant of the Imperator was the Zündapp Citation , built in collaboration with Zündapp, with a 450 cc engine and raised handlebars for the US market.
Test and criticism
In 1956, motorcycle journalist Ernst Leverkus criticized the Imperator engine, which he thought was not fully developed, after attempts on the Nürburgring. The drive chain of the camshaft "temporarily acted as an oil excavator" and pumped too much from the oil reservoir up into the cylinder head. After four sharp laps, something was almost always broken behind the downward slope of the Fuchsröhre , where 7500 revolutions per minute were reached: sometimes the camshaft, sometimes a rocker arm or a connecting rod. However, Horex was able to fix the weak points, so that six months later he drove around 15,000 kilometers with an Imperator team and the engine withstood every load. However, he criticized the "very high vibration frequency", which the driver does not notice in his wrists, but shows up in cracks in the tank, torn fenders and license plates. Regardless of this, he praised the Imperator and the Resident as motorcycles with the most beautiful engines he has ever seen.
Technical specifications
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| Horex Imperator | prototype | Production model |
|---|---|---|
| engine | 2-cylinder four-stroke (OHC) | |
| Displacement | 497 cc | 392 cc |
| Bore × stroke | 65 × 75 mm | 61.5 × 66 mm |
| Power at 1 / min | 30 hp (22 kW) at 6800 | 26 HP (19.1 kW) with 6500 (1 carburetor) 27.8 HP (20.4 kW) with 7350 (2 carburettors) |
| Valve control | Overhead camshaft, rocker arms, overhead valves | |
| compression | 7: 1 | 7.5: 1 |
| Carburetor | k. A. | 1 carburetor: Bing 2/24/29 2 carburettors: Bing 1/24/47 and 1/24/48 |
| cooling | Air cooling | |
| lubrication | Dry sump | |
| transmission | 4-speed gearbox with foot switch (mostly rocker switch ) | |
| frame | Closed double tube frame | |
| Front suspension | Hydraulically damped telescopic fork | Telescopic fork or swing arm |
| Rear suspension | Swing arm with hydraulically damped spring struts | |
| wheelbase | 1400 mm | 1380 mm |
| overall length | 2150 mm | 2140 mm |
| Saddle height | 750 mm | 785 mm |
| Front / rear tires | 3.25-19 / 3.50-19 | 3.25-18 / 3.50-18 |
| Brakes | Light metal full hubs with cooling fins, drum diameter 190 mm, brake shoe width 40 mm, braking surface per wheel 127 cm² |
|
| Empty weight | approx. 195 kg | |
| Tank capacity | 20 l | 17 l |
| Standard consumption * | approx. 4.5 l / 100 km | |
| Top speed | 150 km / h | 135 km / h |
* Consumption at a constant three quarters of the maximum speed, on a flat stretch with no wind + 10
Web links
literature
- Jürgen Nöll: The big Horex book. Motorbuch Verlag, Stuttgart 2008, ISBN 978-3-613-02959-0 .
- Jürgen Nöll: Horex since 1923 (= Schrader type chronicle ). Motorbuch Verlag, Stuttgart 2010, ISBN 978-3-613-03161-6 .
Remarks
- ↑ Jürgen Nöll mentions 1952; However, the first IFMA took place in 1951, the second in 1953. 1953 is out of the question as the year in which the Imperator was presented, as it is depicted and described in words and pictures from 1952 in the catalog 100 Motorcycles . So it must have been 1951.
- ↑ The BMW R 51/3 with 490 cc, 24 hp, cost 3,050 DM.
- ↑ For comparison: The two-cylinder two-stroke engine of the DKW RT 350 built from 1954 to 1956 with a displacement of 348 cm³ developed 18.5 hp at 5000 rpm. The power of the two-stroke engine of the Maico Taifun from 1956 with 395 cm³ was 22.5 hp at 5250 rpm.
- ↑ The felts for lubricating the drive chain are to be soaked with engine oil every 500 kilometers through two lubrication holes in the rubber bellows between the engine and the chain case.
- ↑ The oil in the telescopic fork has to be changed every 6000 km.
Individual evidence
- ↑ a b Kradblatt.de, accessed on October 16, 2019.
- ↑ a b c d e f Jürgen Nöll: The great Horex book. 1st edition. Motorbuch Verlag, Stuttgart 2008, ISBN 978-3-613-02959-0 .
- ↑ Horex-Columbus.de . Retrieved October 20, 2019.
- ↑ Catalog 100 motorcycles in words and pictures . Verlag für Handel und Wirtschaft, Müller & Co., Munich 1952.
- ↑ a b c instruction manual Horex Imperator, 1st edition 1956 . Retrieved October 18, 2019.
- ↑ Ernst Leverkus: The great motorcycles of the 50s. 8th edition. Motorbuch Verlag, 1993, ISBN 3-87943-849-8 , p. 103.