Before Honda created the CB 750 OHC, there was only one heavy, fast, reliable motorcycle: the 594 cc BMW R69S.
The BMW 'Vollschwing' models with their characteristic Earless swing arm front fork were definitive quality products. Globally, the expensive BMWs were not sold. They were bought. There was a Brit who took out an extra mortgage on his house to buy one.
Look for the differences
The R69S was the fastest member of the family. There was also the R50, R60 and R69. The R69S is recognizable by the slightly wider valve covers with only two longitudinal ribs. Another feature is that the exhaust bends run 'in' from the heads rather than fairly straight backwards. The tailored exhaust curve line provided just a bit more ground clearance in the corners. The tailpipes of an R69S are also slightly thicker than those of the R50 and R60.
On the road on a BMW R69S
The first thing that strikes you: The Great & Heavy of that time is over. This BMW is a slender, low motorcycle. After shocking the Bing carburettors, the engine starts after the second stage with its characteristic 'hollow' growl. The choke can quickly come off. The flat almost 600 cc twin is then shaking happily in the frame. Switching of the left-hand gearbox is done with a clear 'Klak'. When the clutch is released, the rear of the machine rises slightly. These are reaction forces of the drive.
The cardan shaft is drawn so 'slim' that it actually worked as a torsion bar and thus made the rigid transmission smoother. The four-speed gearbox works well when the rider is not in a hurry. Before the clutch is operated, some pressure is built up on the gear pedal and then gently upshifts.
The BMW R69S is a fast, but civilized machine
But the R69S would like to be driven a bit higher in the revs. That makes it less suitable as a sidecar tractor. The BMW is also not very temperamental when it comes to cornering. He would like to be sent in emphatically, but the stable bicycle part allows him to follow the chosen lines neatly.
The double cradle frame with its oval-drawn front legs is an example of Teutonic engineering. The beautiful aluminum 2.15 W x 18 rims have 3.50 x 18 tires. The full hub drum brakes are Ø 200 mm (the front brake has two ascending shoes). The tank capacity is 17 liters, optionally 24 liters and with a full 17 liter tank, the machine weighs 195 kilos. The fuel consumption of an R69S was an average of 1 to 18,5.
Two-cylinder four-stroke boxer, a central overhead camshaft, pushrods and rocker arms, two valves per cylinder, bore x stroke; 72×73mm, cylinder capacity; 594cc, compression; 9,5: 1, carburation; Bing 1/26/91, Bing 1/26/92. Power; 42 hp at 7.000 rpm. The 6V electrical installation gets its energy through a Noris magnet. Conversion to 12 V has been accepted and was also done ex works for government engines, certainly in the last construction phase. Ex works, an oil consumption of 0,5 / 1 liter per 1.000 km was allowed.
Its reliability is legendary. Only crankshaft damage often occurred in the earliest specimens. And there were sometimes cylinder rejection phenomena. The maintenance intervals are now very dated. The only concern is the sludge stage in the crankshaft. If it is not cleaned every 30D km, accumulated dirt can destroy the crankshaft. The brake drums may be cracked. The optimal cooling of the boxer twin creates a strange side effect.
The mufflers get less hot than on 'normal' motorcycles. That is why condensed water saturated with acidic residues is not necessarily burnt there. This can cause the dampers to rot. Stainless steel reference is for sale. But they don't sound as good as the original ones.
The key friendliness
Of course, working on a BMW R69S deserves all the respect and attention that the brand is worth. But from an objective point of view, such a BMW is a dream to work on. Everything is easily accessible and of high quality.
The parts supply
BMW cherishes its history. The parts supply 'ex works' is good. But the quality of those reference items (Made in China) is often a bit sad. Certainly for the money that BMW asks for it… In addition, specialists such as De Hobbyist and De Knalpot also supply many high-quality replacement parts.
The price of originality
BMW drivers have an above-average penchant for originality. The R69S involves various bolts with a correct color and impact on the head. They are rare. And expensive. The 24-liter tanks that were optionally manufactured by Heinrich and Hoske do fit within the originality spectrum. The (Hella) 'ossenogen' indicators in the handlebar ends were also available at an additional cost. Oh yes: the tire inflator must be the same color as the engine and the rubber of the timing plug must be white. Meanwhile, R69Ssen are so popular that they are coming again. So watch out for 'fakes' (not to be confused with Dneprs). And the bickering about the right thickness to tenths of a mm of the hand-drawn bebiezing? That is pointless. Because the rushes are hand drawn.
We mentioned in the beginning that Brit who took an extra mortgage on his house to buy an R69S. What if he wanted to score a copy in top condition? Then he would have to take 27.500 euros with him. Because masterpieces always have their price.
Theo Terwels R69S has not been restored. Completely technically overhauled
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