BMW Airhead Engine Gearbox Final Drive Oils

Let´s talk about BMW Airhead oils for engine, gearbox and final drive. A topic that seems to always be a never ending story, and starts well before the season, when it´s time to start the engine after winter storage.

Most any engine oil will work reasonably well for the engine for very basic lubrication. Certain specific ingredients in the engine oil are needed to avoid expensive problems in your BMW Airhead motorcycle. One of them is ZDDP (or ZDP, ZDTP), also known as Zinc. Another ingredient is needed to be sure that under storage conditions, the cam and followers (and some other items in the engine) do not have the oil dripping off and leaving the metal unprotected at engine startup. The final ingredient of major importance is that the amount of detergents, which are Increasingly higher in modern car oils, should not be excessive, as that defeats both long term storage metal protection & the protection of ZDDP.

Most modern motor oils have a maximum of 800 ppm (parts per million) of ZDDP. However, the recommended bare minimum for flat-tappet cam engines and fresh-built engines of all types is 1,000, but most experts agree that 1,200 ppm of ZDDP in your oil is preferred.

If you are thinking of any other brand motor oil than is listed below, you can most likely find out the amount of ZDDP from the oil manufacturers website, from the oils PDS (Product Data Sheet) document, that should list the contents of the oil and amount of ZDDP in ppm.

Gear oils are specified for different temperature ranges, and their additives are most active in those temperature ranges. This is particularly so with the W rated gear oils. An 80 weight gear oil is not as thick as an 80 weight engine oil would be at the same temperature. The measurements, and grades, are very different.

The basic needs for an airhead oils are 20W50 grade oil for the engine, and 80W90 GL5 oil for gearbox and final drive. Below is my list of recommendations for these oils, based on my own research, and reading the details of the product sheets of different oils and manufacturers. Based on these and recommended also by others, I have come to a simple list of different oils that makes it easy to choose based on need.

Just remember to NOT use full synthetic oil for initial break-in.

My personal preference combination with any new and rebuilt bike is Engine Oil #1 + Gearbox and Final Drive Oil #3.

This is what happens to your flat tappet lifters, camshaft and other parts of the engine if you don´t use good or premium quality oil with enough Zinc.

If this happens, you might be looking at a full engine rebuild.

Engine Oil #1

Mineral based oil - Very good option for break in after an engine rebuild as it has high ZDDP amounts. From first 0 - 2500km and onwards. Can be used as The only oil from start to finish. API SF.
MOTUL CLASSIC PERFORMANCE 20W-50 meets manufacturers’ standards from the past, while benefiting from today’s advanced MOTUL lubricants technology.
It is formulated with a unique combination of High Zinc, Phosphorus (ZDDP content >1800 ppm) and Molybdenum additives to provide the best performance for classic cars equipped with large displacement, high performance engines used in hot rods, vintage car racing, etc.
High ZDDP levels offer supreme protection of critical components like high-lift, flat-tappet cams, prone to wear because of the high friction developed in these parts.
Molybdenum has a synergistic effect with ZDDP, lowering friction while increasing the lubricating film’s strength, engine efficiency and power.

Gearbox and Final Drive Oil #1

Motul HD 80W-90 is suitable for all mechanical transmission synchronized or not synchron- ized gearboxes, gearbox/differential, transfer gearboxes and hypoid differentials without limited slip system operating under shocks, heavy loads and low revolution speed or moderate loads and high revolution speed.

ADVANTAGES

Extreme pressure lubricant for an efficient anti wears protection.
Stays in 90 grade after KRL 20 hours shear test as requested by SAE J306 Standard.
Very high lubricating power which decreases friction and wear.
90 grade at hot temperature to provide outstanding oil film resistance at hot temperature and/or to reduce transmission noise.
Suitable for any type of seal and yellow material used in gearboxes design.
Anti-corrosion, anti-foam

Engine Oil #2

Mineral based oil - Good option for break in after an engine rebuild. From first 0 - 2500km and onwards.
High amount of ZDDP (1400ppm)
Our exclusive high zinc and phosphorus formula is engineered specifically for modern and classic high-performance engines both on and off the track, which includes flat-tappet and performance cam motors.
It’s chemically designed to reduce internal friction and enhance power output, while protecting critical engine parts from wear under the extreme conditions of racing.
While its high load carrying characteristics, minimum foaming under stress and maximum resistance to thermal degradation ensure stability and lubrication.

Valvoline Light & Heavy Duty Axle Oil 80W-90

Gearbox and Final Drive Oil #2

Mineral based Valvoline Light & Heavy Duty Axle Oil 80W-90 provides increased protection and lubrication of the differential and the transaxle over a wide temperature range.
Increased protection Increased protection against wear and tear, also under high stress working conditions.
Breakdown resistance Quality base oils and a highly balanced additive system avoid breakdowns even after long-time use.
Advanced additives Consistent, stable viscosity. Modern additives protect against corrosion, oxidation, Increased viscosity-temperature properties even at foaming and deposits. very low temperatures. Highly stable viscosity with long-term multigrade advantages.

Redline HD 20W50 Motor Oil Full Synthetic

Engine Oil #3

Fully synthetic - excellent option after engine break in and engine driven over 15000km
High amount of ZDDP (2200ppm)
Superior film strength through the use of ester base stocks for protection and ring seal
Extended drain intervals over other brands due to higher quality base stocks and excellent dispersants
Blended with specific friction modifiers that are compatible with wet-clutches
Suitable for JASO MA/MA2 API SJ/SG/SH applications

Redline Heavy Shockproof Gear Oil Full Synthetic

Gearbox and Final Drive #3

Film thickness greater than an SAE 75W250, yet low fluid friction like 75W90

For heavily-loaded racing differentials and transmissions, problem gearboxes
Most popular ShockProof product, many racing and specialty applications
Many performance racing applications like Sprint, Midget, Dirt Late Model and Quick Change Differentials, Detroit Lockers and spools, NHRA Top Fuel and Funny Car rear ends
Not recommended for most synchro applications due to the product's extreme slipperiness