BMW mono suspension boxers

ER Classics Desktop 2022

A lot of BMW two-valve boxers are currently being converted into unique machines for youthful bearded men. The rinsing on good, original specimens becomes thinner. And that also applies to the latest BMW two-valve boxers: the machines with mono-suspension. And there is a lot to be said about those models.

Reborn Boxers

The Boxers were the return of the species. Because at BMW, after the introduction of the K75 and K100, they had thought that the boxing era would be over. But the clientele thought differently. BMW brought the two-valve boxers back, with the R80 still being developed as a starting point. It now had the reinforced frame of the R45 / R65 BMWs. And monovering behind. After 1985, these engines were factory-fitted for unleaded petrol.

The accountant decided

With this generation, BMW's great quality thinking had faded into the background. Margins had to be made, while prices (Japan!) Were under pressure. As a result, these BMWs are slightly less finished. The frames rust earlier. The bolts and nuts optically have a shorter service life. The centerstand has a tendency to sag that did not occur before. With a jacked-up mono, the rear wheel must float 3-4 cm above the ground. Otherwise there is (welding) work to be done.

Play in the transmission

The free stroke of the rear wheel may only amount to one fifth before the transmission train starts to move. Raw noises and or crackling mean lower and or universal joint damage. The spring element has a service life of approximately 50D km. That is the same mileage where the replacement of the main nozzles and gas needles should be considered. And then also replace the distribution chain. The needle bearings of the tumblers also sometimes want to break. You will then usually find the needles in the oil pan.

The fill and drain plugs

At the rear, near the cardan clock, the fill and drain plugs for the oil are sensitive to mad wire. Do not use copper as a sealing ring, but soft aluminum sealing rings. The copper specimens can tighten the thread when they are tightened until they are sealed. Because they are simply too hard.

The front silencer in the exhaust system is rust sensitive

The dampers themselves can also rust firmly. And the ring nuts of the exhaust pipes tend to get stuck seriously. But a reasonable approach is to give them a shot of crawling oil every day for two weeks. Only use the specially designed crown wrench when loosening. Often, careful cutting of the cable glands is the only option. Plastic parts have regular cracks and breaks. This certainly applies to the attachment pins of the side covers and lower body parts.

The ball bearings

The ball bearings are usually the turn of 70D km. The replacement is not super easy. The housing of the counters is often broken, but is now for sale as a replacement part. New brake discs (service life approx. 100D km) are quite expensive.

Leakage along the rubbers

The rubbers at the pushrod tunnels and those at the oil pressure switch tend to leak. If there is oil in the 'valleys' under the tank, the rear crankshaft seal must be replaced. And that is quite a job.

Still very good motorcycles

With these comments, these BMWs are still very good engines that are certainly not inferior in terms of quality to the Japanese competition. But the differences with the / 5 and / 6 machines are undeniable.

Pay attention to damage to the plastic parts

Tumbler shaft bearing needles. From the crankcase
At 100D + km the dots are nicely worn around
The front discs last approximately one ton

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