On the move: BMW R 26 and Simson AWO 425 S.


On the move: BMW R 26 and Simson AWO 425 S.

In comparison: BMW R 26 and Simson AWO 425 S.

Same parts – BMW R 26 and Simson AWO 425 S.

Content of

Because they didn’t dare dream of their own car in the 1950s, many Germans concentrated their longing on a beautiful, well-established 250cc. In the west as in the east.

BMW R 26 and Simson AWO 425 S

The coarsest dust was shaken off, the wounds licked and the horror stowed away. You had a place to stay again, a job, friends and family. One had learned or one had forgotten. The Germans wanted to live, to finally live well again, to move forward, to the sun, to freedom, to the swimming pool, whatever, the main thing was fast, and whoever wanted to keep up needed more than a moped. A good 15 years after the start of the war: Here the FRG and there the GDR, not yet separated by a wall, but with clear dividing lines. Market or plan, NATO or Warsaw Pact – 15 years change a lot. And they change little: the motorcyclists here and there counted their savings again. A quarter-liter machine, man, that would fit. Preferably ventilated in four-stroke, because that is impressive. Four bars cost more than two, they make the right note.
In the west, the favorites were NSU and BMW, with the Neckarsulmers emphasizing a more sporty note and the Munich-based a more dignified touch. In the east, the most coveted motorcycle came from Simson from Thuringia, and because the products of the last two brands have so many similarities, today, 57 years after their debut, they are being compared in MOTORRAD CLASSIC. BMW R 26 and Simson AWO 425 S, peacefully and happily united for a cozy country party.
D.he meeting takes place near Zwickau in Saxony, in a neutral area, so to speak. Or with the common opponent, as you like, because for many years the most successful two-stroke engines in the world came from Zschopau – not even 50 kilometers away as the crow flies. Even under Soviet direction, they were to come off the production line en masse again soon after the end of the war in the former DKW works. So the people in Suhl were all the more astonished when in 1948 the order was received that the former armory Simson should start the production of a four-stroke motorcycle. All specifications were very precise, all indicated that those responsible had taken a very close look at the well-proven BMW single-cylinder.

No wonder, because not only Simson and some smaller mechanical factories in Saxony and Thuringia, but also the former BMW plant in Eisenach were part of the training of the new owners, the Soviet joint-stock company Awtowelo. The Germans were no longer allowed to manufacture weapons, cars and mopeds had already been produced in Suhl – so they should now try a motorcycle. Dawei, dawei, and if you have any questions you can turn to your experienced colleagues from Eisenach. Against this background and in view of the material situation in the Soviet occupation zone, it must be regarded as a medium miracle that the engineers – with the help of the renowned designer August Prussing, Auto Union’s race director before the war – kept the deadline and presented two prototypes in 1949. The following year, the first four-stroke engines from Suhl roared through the newly founded GDR. Its name is firstly derived from Awtowelo and secondly stands for four-stroke and 250 cm³: AWO 425.
The AWO was jewelery and useful; production rose in no time from 7,300 pieces (1951) to over 20,000 (1955). So the attempt was made to continue this success with a more modern parallel model. The S model was commissioned as early as 1954, production started in December 1955, and all the experts were amazed at the building blocks: Simson not only met the rapidly increasing requirements technically, but the new S also proved to be a pretty child of its time. Beautifully exhibited curves of the fenders, successful lines, modern two-man seat, painted rims – a poem.


Which for whom? They are both chic in any case.

In comparison with the basic model, henceforth called T for Touring, only the engine looked familiar. A misjudgment, because even the more angular cooling fins reveal considerable changes here too. The aerodynamic incline of the carburetor is also noticeable. Fallstrom looks different, but still: enough talked about, let’s hear it! The Suhl stew doesn’t last long. Carburettor flooded, one – but really – courageous step, one more, and already it spreads its pleasantly deep and surprisingly robust melodious sound. It is allowed to warm up for a moment while idling, then the machine is pushed off the main stand. Your driver can expect pleasant space and a well-shaped bench. The single-disc dry clutch requires little manual force, first gear engages exactly, a little gas, then the single-cylinder pushes. Like all engines with a good flywheel, it has sovereign power. He persistently turns up, the first gear translates to astonishingly “long”. Every shift is accompanied by a gentle caress on the right lower leg; the reason for this obtrusiveness is quickly identified as the small manual gearshift lever that the S with the unchanged transmission has taken over from the T. It seems lost and old-fashioned in this overall contemporary design.
A 425 S takes almost all of the surrounding hills in fourth gear, but even the heights of the Ore Mountains that greet you from afar are not really frightening: the easily shiftable gearbox, the relatively wide available speed range of the engine and the decent, easily controllable brakes arouse a thirst for adventure and allow a brisk driving style. The tight spring elements have no trouble with modern roads, even patched asphalt master them with dignity. With impressive accuracy, the Simson hurries through narrow and wide radii, but to the right, the rather deep silencer limits all too sporty activity.
As usual, Simson aimed at all European export markets with the S, which is why the Suhl company sent some demonstration pieces to the German IFMA in 1956. There was a rendezvous with the brand new BMW R 26, but not the exciting East-West duel. No, the script was unfortunately different: in all the richer western countries, customers switched to cars, and designs that were as bizarre as they were questionable made the transition easier. BMW also sold such a vehicle with the Isetta; it cost only 400 marks more than the R 26.

Its predecessor, the R 25/3, was the best-selling BMW motorcycle until a few years ago and found around 47,000 customers between 1953 and 1956. However, the line of ancestors can be fully traced back to the R 2 from 1931, whose engine also provided all the design features for the post-war singles. It was specially created for the low-insurance 200 series; only based on the successor R 20, a 250-series BMW emerged in 1938 with the R 23. Back then, the Munich-based company acted as pioneers of the telescopic fork, and the R 25/3 still felt obliged to this spirit.
And then came the full swing chassis. As if it was not the Briton Ernest Earles, but the Mother of God herself who had been sitting at the drawing board, the front long-arm swing arm was raised to be the bringer of salvation for bad and good, for winding and straight roads. The boxers, renovated last year, had started with it, accompanied by a real campaign by BMW. The higher weight was supposed to be offset by improved suspension properties and increased stiffness, even in racing the boxers wore the Earles fork – and were feared because these front suspensions swallowed almost everything, but could then kick back without notice. The swing arm had undoubted advantages in combination operation, thanks to the double mountings for the swing arm axle, it was easy to reposition and thus adapt the geometry.
The BMW engineers finally gave the engine of the R 26 a cool head – the predecessor was even supposed to be black in color to promote heat radiation, which people then called not the cylinder head, but the Moor’s head. That was no longer necessary, completely unpainted, the ohv single gave 15 hp to the four-speed gearbox. Not spectacular, the NSU Max had more, not to mention the Supermax.
BMW drivers aren’t interested in that? They don’t want to be fast? Everything is a lie! They devoured the test in Das MOTORRAD, which certified them in 1956: “The R 26 offers a chassis that represents an optimum in the middle class and which in some points forces a reorientation.” Among other things, with regard to the meaning of bare horsepower figures . The BMW was fast because you rarely had to take off the accelerator. It kept calm even on bad ground and followed the steering commands willingly and precisely.


Accurately and easily rush through Simson and BMW curves of all kinds.

And why does Samson stay at it so indefatigably? Well, because specialist Rene Nawrath not only restores perfectly, but also with a focus on performance. And because there are no more bad roads. In any case, none that made an AWO telescopic fork look really old compared to the BMW long swing arm. Nevertheless, just a few kilometers testify to the outstanding ride comfort of the R 26 and the utterly astonishing responsiveness of the front suspension. And because specialist Uli Seiwert has reassembled the original spring-loaded single seat, the BMW driver really glides through the Zwickau countryside as if carried on a sedan chair. Great, and by no means bought at the cost of absurd damping – the R 26 stays on course even on undulating ground. Despite the relatively high weight of its front suspension, it turns in very spontaneously, even requiring a short familiarization, as it changes direction so lightly.
The engine performance starts a little more gently than with the Simson, but the performance curves of the two driven machines should be almost identical. They also vibrate in unison, but the rubber mounts on the BMW handlebars hold back a lot. The effective soundproofing fits the image of the gentleman bike: The BMW is so quiet that the MOTORRAD colleagues 55 years ago feared for road safety, because children playing and women gossiping could overhear them. Well.
Both motorcycles – and that is also part of this story – had a second life. Thanks to their high level of reliability, many R 26s survived into the 1970s and served school and college students as dirt-cheap entry-level motorcycles. Then at the latest the single seat flew away. If there was still enough money, chrome mudguards were used, in any case the good BMW got louder, sometimes it was even chopped.
The Simson, however, promoted a whole motorcycle subculture, because after the production stop ordered from above in 1961, all four-stroke fans clung to the Suhl stew all the more doggedly. Especially those who wanted to do Easy Rider in the GDR. BMW R 26 and Sport-AWO, deprived of their ornaments, as a means of expression of a rolling freedom movement – sometimes a hell of a lot changes in a good 15 years.

In detail: BMW R 26


In detail: BMW R 26.

Data (type R 26)
Engine: Air-cooled single-cylinder four-stroke engine, an underneath camshaft, two valves, operated via bumpers and rocker arms, displacement 245 cm³, output 11 kW (15 PS) at 6400 rpm
Power transmission: Single-disc dry clutch, blocked four-speed gearbox, cardan drive
Landing gear: Double loop frame made of steel, pushed long arm swing arm at the front, swing arm with two spring struts at the rear, tires at the front and rear 3.25 x 18, drum brakes, Ø 160 mm at the front and rear
Measurements and weight: Wheelbase 1390 mm, weight with a full tank of 158 kg
Driving performance: Top speed 128 km / h

Consistent development work resulted from the engine of the esteemed and proven R 25/3 that of the R 26. First and foremost, BMW improved the heat balance of the cylinder head, which is why the new head has significantly larger cooling fins. At the same time it was thermally optimized inside, as a result of this conversion work, the spark plug moved from the left to the right side of the engine.
The cross-sections at the inlet and carburetor grew, the compression rose from 7.0 to 7.5: 1, and the power increased by two to 15 hp. If the R 25/3 had sucked in its combustion air under the tank, the intake pipe was now aimed straight back into a tinny air filter box. This also took on the 6-volt battery. The changes to the chassis are clearly visible: While the R 25/3 still had a telescopic fork at the front and straight-way suspension at the rear, its successor relied on the full swing chassis introduced by the Boxers in 1955. At the time, it was considered to be unrivaled comfort and can still inspire today in this regard. At the same time, it had great advantages in sidecar operation, which many R 26 machines still had to do. Initially, the articulation points for the sidecar were directly available, later a subframe available from BMW had to be screwed on.

The materials used and the careful assembly made BMW motorcycles special in the 1950s, and these qualities still pay off today. Nevertheless, there are weak points, the most common being the alternator. It should always be in good shape, and thanks to a good supply of spare parts it can do that too. The battery-powered ignition is happy about a full battery, which in turn has a modern electronic controller. Something new: Gel batteries cope better with low charging currents, and they are also available in 6 volts for the R 26. Mechanically, the engine is considered to be very healthy with good care, the only exception being the rear crankshaft bearing. In the case of the R 26, of course, good care means that the oil level in particular must always be monitored. The capacity is a modest 1.25 liters, which is why everyone who regularly moves their oldie single is happy to convert to a larger oil pan. When it comes to the chassis, the bearings of the two swing arms deserve particular attention, and if a sidecar has ever hung on the R 26, the front swing arm should also be checked for distortion.

Almost 2000 of the R 26 are now registered in Germany, less than half as many as the R 25’s predecessor. However, the number is likely to be much larger – today, many examples only decorate the garage or hallway. It’s a shame, because the R 26 is definitely a classic with everyday suitability, not least thanks to the secure supply of parts. The usual BMW surcharge is also due here, good and ready-to-drive specimens are hard to get under 4000 euros, but above 6000 euros an absolute top condition can be expected.

Ulis motorcycle shop
Phone 069/175 36 44-0
BMW Classic Rabenbauer
Telephone 085 81/9 87 87-0 www.rabenbauer.com

Clubs and forums
BMW single cylinder information center

BMW Veterans Club Germany

In detail: Simson AWO 425 S


In detail: Simson AWO 425 S.

Data (Type 425 S)
Engine: Air-cooled single-cylinder four-stroke engine, an underneath camshaft, two valves, operated via bumpers and rocker arms, displacement 247 cm³, output 10.5 kW (14 PS) at 6300 rpm
Power transmission: Single-disc dry clutch, blocked four-speed gearbox, cardan drive
Landing gear: Double loop frame made of steel, telescopic fork at the front, swing arm with two spring struts at the rear, tires at the front and rear 3.25 x 18, drum brakes, Ø 180 mm at the front and rear
Measurements and weight: Wheelbase 1375 mm, weight 156 kg with a full tank
Driving performance: Top speed 110 km / h

The 425 S was not intended to replace the standard AWO model introduced in 1950, but to complement it. Therefore, the latter traded under the name T for Touring from 1956 and was produced until 1960. There are of course close technical relationships, but there are also major differences in some cases. The first thing that catches the eye is the rear swing arm instead of the straight-path suspension and the longer fork, the front and rear of the S was able to provide significantly longer suspension travel. The now 18-inch wheels had impressive 180-mm brake hubs made of light metal, which were able to cope with both a sporty pace and teamwork. The S also had the connection points for a sidecar as standard, and the ratio of its cardan drive could be adjusted.
Outwardly, the engine differs from that of the T in its even larger and almost rectangular shaped cooling ribs on the cylinder head. Its light metal cylinder initially had a shrunk-in, later cast-in liner. A lightened valve train and harder hairpin valve springs allowed higher speeds, the carburetor that was just attached grew a little, the combustion chamber was redesigned, the compression increased from 7.2 to 8.3: 1 and in the end the triple ball bearing crankshaft 14 balanced, later then 15.5 hp to the unchanged four-speed transmission.

The striking blow of the Simson single cylinder has not only good (sound), but also less good sides (vibrations). Initially, it is said to have even broken the frame cover due to violent vibrations. From the end of 1959 the engine was rubber-mounted, and after that there was deep peace, because the simple and carefully arranged technology of the AWO rarely causes stress in everyday life. Bad can end up if the battery boils over due to a defective regulator. It sits exactly above the muffler. The engine doesn’t need a battery to start, but its magneto needs a fairly high speed. So keep on kicking, but even more energetically, if it doesn’t ignite immediately. With the regulator, magneto and alternator armature, the original parts that are most susceptible to failure are also mentioned. During the GDR era, the AWO was often tinkered with or rebuilt, after the fall of the Wall, some things were quickly restored. If you are looking for an original, you should do some research beforehand or take an expert with you to visit.

Around 85,000 Sport-AWO have been built, similar to the BMW in the west, it had a particularly high priority in the east compared to other motorcycles. Nevertheless, the beautiful people from Suhl are gradually making themselves scarce. Above all, they now achieve prices that – and rightly so – are on par with western motorcycles. The early models with the 14 hp engine are particularly popular because they are less common. Basically, well-restored and technically flawless specimens cost around 3500 to 4000 euros, technical and optical beauties like the photo model shown in this story sometimes come in over 6000 euros. Unrestored it starts at between 1000 and 2000 euros. The spare parts situation is extremely relaxed, missing original parts are usually reproduced in good quality.

Rene Nawrath
Telephone 0375/204 86 98

Clubs and forums
AWO forum
IG for the preservation of East German motorcycles “East Bike United”
Hilles AWO Site

Strengths and weaknesses


BMW R 26 and Simson AWO 425 S in comparison.

Our opinions

Anton Semerikow, on the BMW R 26
Admittedly, as a youngster you have to get used to the bulky BMW transmission, but otherwise I was amazed at how tame and above all comfortable the R 26 is. A 50-year-old 250 with full suitability for everyday use – great.

Fred Siemer, on the Simson AWO 425 S
As is well known, the R 26 is a top product of its time. I had not expected – ashes on my head – that Simson would meet the BMW at eye level. The comfort is a little worse, the gearbox much better, with the rest of the tie.

One thought on “On the move: BMW R 26 and Simson AWO 425 S.

  1. I have a awo for which I am not able to find a single example
    The frame is identical to a r 27 bmw.
    Were there some machines made by copying the na bmw ?

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