The manufacturer of BMW motorcycles did not envisage checking the oil level in the gearbox.
As a rule, if there are no suspected oil leaks, the level should be correct.
It turned out, however, that this theory is not entirely true in the BMW two-valve boxers.
Well, the line of the counter drive (speedometer) is driven directly from the box, and its seat is sealed with a rubber cap.
After many years, the rubber of the cap cracks and crumbles, which causes water to enter the box, mixing water with oil, and we have a water-oil emulsion instead of oil. Such an emulsion, instead of lubricating it, very quickly leads to premature wear of the box.
The sight glass offered here allows you to control the quality and level of oil lubricating the gear.
This product can also be used in newer BMW motorcycles without any obstacles.
The assembly is very simple - just unscrew the original plug and replace it with a gasket, not forgetting a new plug gasket.
