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10w 40 semi synthetic


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Hi I use 10w 40 semi synethetic engine oil in my 2004 1150RT, is it better to use fully sythetic oil & if so what grade?


What about semi or fully synthetic for final drive & gearbox.


New plugs fitted yesterday, valve clearance & rocker clearances adjusted, now running great. :wave:

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John, it depends on what you mean by BETTER.. Remember Semi-Synthetic is more of a marketing term than an oil quality term.. To be sold as a Semi Synthetic it can be about any oil from a decent based oil to a very poor quality base stock.. All it has to do is contain a certain (low amount) of synthetic products (synthetic what?)..


Good synthetic oil costs a lot to make so keep that in mind,, a $3.00 quart of oil is probably worth all of $3.00.. An $8.00 or $9.00 quart of oil has a much better chance of containing better base & synthetic stocks.. Now buying a $9.00 quart of synthetic oil on sale for $4.50 is not a bad thing..


The ONLY way to know if the motor oil you are buying is what you really want to use is to do the research & see what it contains,, & what test specs it really meets.. Would you buy a gallon of milk that said Semi Synthetic on the side of the jug without knowing what was real & what was added in synthetic form?


The majority of synthetic (or semi synthetic) oil (sold in the U.S.) is mainly due to marketing hype not oil quality..


Just make sure whatever oil you choose meets the oil specs printed in your owners manual..


Same with the trans & final drive.. Buy quality with known (& researched) specs not by some catch phrase name like Semi Something or other..


Bottom Line Here: (exactly what is in the darn stuff you are buying?)





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as we do not get the high-temperatures that are seen in many US states, nor do we have to sit in stationary traffic, fully synthetic oil brings absolutely no benefit. As long as the oil is to BMW specs it is just fine.


FWIW, I am currently using Miller ZZS 20-50 as it has higher levels of ZDDP than other offerings on the market.



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Hi thanks for the guidance


Was it this oli you meant?



ZSS 20w50



A high performance semi-synthetic competition engine oil for 4 stroke motorcycle engines requiring a SAE 20w50 viscosity.

Based on the highest quality performance additives and shear stable viscosity improvers in synthetic and mineral oils.



Use as received for lubrication of 4-stroke motorcycle, kart and scooter engines specifying a SAE 20w50 viscosity.



• Semi-synthetic formulation.

• Sophisticated performance additive package.

• Provides maximum engine protection.

• Viscometrics reduce oil consumption making this oil particularly suitable for long distance events.

• Formulated to provide high temperature viscosity at the top limit of an SAE 50 which ensures that oil pressure will be maintained under extreme conditions.

• Suitable for use in machines fitted with oil immersed ‘wet’ clutches.




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  • 2 weeks later...

Ed, that depends on the miles on the bike & (if) it is still using any oil..


Even then I wouldn’t post it here as these threads go into archive & as fast as modern motor oil’s change their ingredients that means XXXX brand can be great today & wrong for a motorcycle a month form now..


If you want to know what I am personally using at the moment just PM me & I will answer you..





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MY 06 rt has 3k miles on it. I know, it's a baby. I wouldn't go for the fully synthetic until I know it's done burning oil and therefore somewhat broken in. And whats a pm? and how do I do that! (personal message?)

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My 1100 RT started breaking in around 40000km and is

still loosening and getting smoother at double that distance. I sometimes put 250ml between 10000km services and that usually overfills to above the dot. I use Castrol GTX 20W-50 FWIW.


It's my belief that oil consuption on these boxers is a function of the type of breather used. The RT is a 2001 model and has the double sealed rear main bearing and breathes from between the seals with the closest "web" of the crankshaft drilled to feed fumes to the above area and thereby also offers a form of centrifuge oil seperation. From time to time I get a couple of drops of oil out the airbox drain.


My '96 R850R does not consume a drop of oil between services and it has the older centrifugal seperator mounted on the front of the crankshaft. I never get any oil in the airbox.


Of course your '06 model has a very different breather system and there have been excellent writeups on it on this board as I recall probably some 6 or more years ago...

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As long as we are on the question, I changed the oil in mine today with Mobil 1 15w50 which is full synthetic. Cost me thirty bucks for 5 quarts on sale. I'm gonna need the 5th it burns some.


I know it doesn't change ALL the oil because the cooler is full, so I mixed Valvoline 10w40 the previous owner used.


I got the filter off no problem, but need a better way to tighten the new one on. Not much room for a wrench in there. Going out tonight to see if I can find one.


David :)

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Autozone $5.00.


I borrowed a 3/8 rachet while I was at the store "to make sure the filter wrench fit the filter" I really wanted make sure I had it tight enough.


David :)

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Shell Rotella 15-40 as diesel oil is supposed to contain more zinc and it meets all oil specs called for in the owners manual. Can't see synthetic because I don't operate motorcycles in winter so no cold starts which is about the only thing a synthetic is good for other than deflating your wallet. I use Mobil One in my autos and change twice per year because they are exposed to winter conditions that are extreme at times. Well, my Mustang doesn't operate in winter so only change oil once per year in the fall with Mobil One.

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Take the old filter to your local autostore and try the various cup-wrenches to find the one that fits, or buy one from BeemerBoneyard, or you local dealer - the last one is the expensive option.



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I always ran 15W40 diesel oil in my /6. Its good stuff.


For the synthetic, I put synthetic in my diesel truck so it starts in the winter.


The thing that got me using it more is the owners manual said NOT to use it in my air cooled 2 cylinder welder until after 50 hours of use so it will break in.


If my R1100RT burns as much oil as I think, I will switch to the rotella. Its cheaper.


So no concerns of mixing the synthetic and mineral oil?



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David, you can easily mix synthetic engine oil with conventional engine oil.. In today’s oil market (especially in the USA) there is very little difference between conventional oil & synthetic oil base stock wise.. Most BIG oil companies have started making their synthetic oil from conventional oil base stock,, a few like Amsoil still use a PAO base stock but most just start with conventional Dino oil.. It has more to do with the refining difference & additive package than base oil stock..


It’s the additive packages IN the oil that sometimes are not totally compatible.. Even then it won’t outright hurt anything it has more to do with long drain intervals..


On the Rotella-T (dino 15w40) ,, keep in mind that oil has changed since it went to the triple protection formula.. It is now a soot control oil that is Diesel emission friendly.. It is also now an SM/SL rated engine oil..


The Rotella-T synthetic (well sort-of-synthetic I like to call it) (5w40) is a little better as a motorcycle oil.. The Rotella-T 5w40 is still an SJ/SL rated engine oil but it also carries an SH rating..


Run your bike while to see if it is still using engine oil.. Keep in mind they will sometimes quickly go down about ½ quart then quit using any more oil.. The BMW boxer holds a LOT of engine oil so ½ quart low still leaves a lot of oil in the engine..


If your BMW boxer still uses a fair amount of oil even operating ½ quart low give me a PM as I have a couple of oil recommendations for reducing the oil usage a little more..




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