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I remember in my family's Triumph Dealership in the mis 1960's that we carried Castrol NON-detergent oil and used it to do oil changes and I believe it was recommended by the factory- not the brand but the non detergent spec. Those bikes were dry sump but had roller cranks and big end bearings. There was no oil filter and we understood if detergent oil was used it carried the dirt (and other particulates) throughout the engine to its detriment. Could the same be true for BMW and especially for the Slingers. Those particles being slightly more dense than the oil are centrifuged out and fill the slingers. In fact the early BMW slinger design may precede detergent oil. The dirt might then accumulate in the pan not in the slingers? I will be cleaning the slingers of my newly acquired 1959 R60 soon and am considering getting a properly rated quality SAE 40 weight for it. I have heard about Shell Rotella and can do that if its a better idea. I am new to the forum please be kind if this is a DUM thought.

You are 100% correct. A good, non-detergent oil is really the best in terms of the slingers. As you suggest, the particulates will have more of a chance to settle to the bottom of the pan when the bike is resting. The only thing that I would worry about indepedent of whatever oil is used, is to ensure that the bike has the specs for the time period and one of those things that have been determined to be good for these flat tappet engines is ZDDP.

That said, a good multi-vis, SG/SH rated oil, changed often will likely serve you quite well.

Kurt in S.A.

rdnhaz wrote:I remember in my family's Triumph Dealership in the mis 1960's that we carried Castrol NON-detergent oil and used it to do oil changes and I believe it was recommended by the factory- not the brand but the non detergent spec. Those bikes were dry sump but had roller cranks and big end bearings. There was no oil filter and we understood if detergent oil was used it carried the dirt (and other particulates) throughout the engine to its detriment. Could the same be true for BMW and especially for the Slingers. Those particles being slightly more dense than the oil are centrifuged out and fill the slingers. In fact the early BMW slinger design may precede detergent oil. The dirt might then accumulate in the pan not in the slingers? I will be cleaning the slingers of my newly acquired 1959 R60 soon and am considering getting a properly rated quality SAE 40 weight for it. I have heard about Shell Rotella and can do that if its a better idea. I am new to the forum please be kind if this is a DUM thought.

I have been positing the same DUM thought for these many years. Yes, slingers preceeded detergent oil. If people want to do slingers every 25 k miles, OK, it is their money.

Before detergent oil, it was common to get 100 k on a lower end, not now.

What viscosities are acceptable?

http://www.grainger.com/Grainger/VALVOL ... ts-_-1UBY5

If http://www.morrislubricants.co.uk/scrip ... tegory=139 is avaialble on this side of the pond it would be nice.

I'm still not certain that detergent oil is the primary culprit in filling the slingers in fewer miles. It's been brought up before that these bikes are 50 to 60 years old now, and almost all of them (that are running) have spent long periods of time sitting unused. Any corrosion taking place inside the cylinder walls ends up being scraped off and then ends up in the slingers. A very small amount of rust on the cylinders can very quickly overwhelm the slingers.

I understand the detergent vs. non-detergent reasoning, but that is not the only difference between these bikes now, and the same bikes 50 years ago - the biggest difference is that they are 50 years older.

So your answer, Major, would be to start with a freshly gone-through engine, and ride it every day, as if it were your only bike.
Then make sure it is at TDC for the winter, preferably parked in your living room, and come Spring, perform a couple of low-mileage oil changes.

R65 Rob wrote:So your answer, Major, would be to start with a freshly gone-through engine, and ride it every day, as if it were your only bike.
Then make sure it is at TDC for the winter, preferably parked in your living room, and come Spring, perform a couple of low-mileage oil changes.

No.

Assuming that the reason 50 - 60 year-old bikes fill their slingers in fewer miles than 5 - 10 year-old bikes is because of the use of detergent oil is faulty logic. It is equally possible that the cause is that they are 50 - 60 years old instead of 5 - 10 years old.

The important part of my point is: if those decades of sitting around truly is the major contributor to the problem, then using an inferior lubricant for the purpose of trying to prevent slinger filling is not going to accomplish the desired goal, and you are better off trying to protect the moving parts by using the most effective current motorcycle lubricants.

The "answer" is that we would all be much better off knowing exactly what the truth is, but I don't think that's likely to happen. Basically, we would need a few old original bikes that had never run detergent to keep running non-detergent, and then, after 40k miles or so, compare their slingers to those of some bikes that had been restored to mechanically new condition and ran Spectro Platinum or Motul 300V (or something similar) for 40k miles. I don't see this comparison as being very likely to occur.

Is there a 10-year old motor vehicle that uses slingers?

R65 Rob wrote:Is there a 10-year old motor vehicle that uses slingers?

Are you being intentionally obtuse?