Oils are essential for the long-term, sustainable lifespan of machinery. This is especially true for our motorcycles.
When it comes to oil changes, engine oil naturally comes to mind first. However, there are other components that also have their own oil reservoirs, whose oil levels must be checked regularly and changed according to the manufacturer's specifications. In addition to the regular engine oil change, there’s also the gearbox oil, final drive or shaft drive oil (on shaft-driven BMWs), and fork oil. The required quantities and specifications can be found in the technical documentation for each machine – and must be strictly followed.
Regular Oil Level Checks
All oil levels should be checked at regular intervals. This can often be done in passing with minimal effort. Depending on the model, either classic dipsticks or oil inspection windows with MIN and MAX markings are used. The oil level must be within these two markings — not above, not below!
On newer models, oil checks or indicators are increasingly found in the multifunction display of the rider information system.
Special Feature: Oil Dipstick
Warning: When using an oil dipstick, it is especially important to insert it correctly. Otherwise, the reading may be inaccurate, as many dipsticks are meant to be placed in rather than screwed in for measurement! The owner's manual provides more detailed instructions on this.
When it comes to engine oil, we differentiate between machines
- with separate oil reservoirs for engine and gearbox
- or a shared oil reservoir
In the first case, the specifications for engine and gearbox oil may differ. This is often the case for many BMWs with shaft drive and a so-called dry clutch.
Most motorcycles with a shared oil sump for engine and gearbox feature a wet clutch, whose discs run in the oil.
Warning: In such cases, special attention must be paid when using oil additives. Overdosing can cause the clutch to slip or even require replacement.
Oil Consumption
Unlike engine oil, where manufacturers tolerate a certain level of consumption for technical reasons, there should be no oil consumption in the (separate) gearbox, final drive, or fork. If the oil level is correct after a change, any drop in level would typically be due to a leak. Such leaks usually develop gradually and often start with the appearance of an oil mist.
Excessive engine oil consumption beyond factory specifications indicates engine wear. This could be caused by worn piston rings, pistons, or valve stem seals.
Oil Temperature
Normal engine oil temperatures in a fully warmed-up engine range between 80°C and a maximum of 120°C. The oil temperature depends on ambient temperature and engine load. High loads and elevated oil temperatures typically occur during spirited riding or with heavy payloads.
Oil coolers can help optimise the engine’s temperature balance. It’s important to factor in the oil volume required by the cooler when determining the total oil quantity.
Oil Sumps
Technicians refer to the oil sump, usually meaning the oil pan into which the engine oil drains back. Many motorcycles are equipped with an oil sump, also known as a wet sump.
In contrast, the more advanced dry sump lubrication system is typically used in high-performance sport or off-road motorcycles, where the oil is stored in a separate tank.
In a wet sump system, oil starvation can occur when the oil moves excessively and the oil pump temporarily fails to draw it in. Unlike in powerful sports cars, lateral acceleration in corners plays a smaller role in motorcycles, since centrifugal force tends to push the oil toward the sump during cornering. However, sloshing or splashing of oil forwards and backwards is much more relevant on a motorcycle due to its extreme positive (acceleration) and negative (braking) G-forces.
Oil Filter
The oil filter plays a vital role by removing all unwanted particles from the oil. These include wear debris and combustion residues. In addition to lubricating, the oil keeps these residues suspended until they are captured by the oil filter. Regular replacement of the oil filter is therefore essential.
What Else Should You Keep in Mind?
With the right technical know-how and a good model-specific guide, changing the oil for the engine, gearbox, and final drive is relatively straightforward. The fork, however, should be serviced by experienced professionals.
We generally recommend replacing the seals on the drain plugs and, where applicable, those on the filler plug or dipstick with new ones. All gaskets around the engine oil filter should also be carefully oiled and replaced.
Environment
Used oil, removed filters, and seals must be disposed of in an environmentally responsible manner.