Kindergarten Oil question

[Deleted member 1344]

Every one knows that quality oil will lengthen the life of mating parts in an engine drive mechanism. Good lubrication means the metal surfaces mate on a thin film of oil.

But what if the oil is of such high quality (can I say slippery?) that it causes the clutch to slip? In this case the oil needs to have better friction properties.

Most motorcycles and dirt bikes use the same oil to lubricate the engine and clutch. Now think about this oddity......
1) We would like the oil to provide a frictionless environment for the engine.
2) We would like the oil to have proper friction grip to prevent clutch slippage.

Why would a motorcycle manufacturer design a wet clutch system given the above two contradictory goals? Yes I must be in kindergarten as this makes no sense whatsoever. Thank the good Lord our R18 family of bikes have dry clutches.

 

[adamchandler]

I thought the R18 was a dry clutch and you have separate reservoirs for engine oil & transmission fluid?

Even though, specifically if I'm wrong, the JASO MA2 spec actually addresses what you're talking about -

It's formulated for even the S1000RR and 1290 Super Duke who both use wet clutches and have a lot of torque. The big advantage of MA1 versus MA2 was the clutch friction is better in high power applications.

I'm not an engineer but I really thought we had a dry clutch.

YEP:

Just like the pre-liquid-cooled boxers produced before 2012, the R18 utilises a single-plate dry clutch. BMW’s engineers mentioned that the clutch incorporated an anti-hopping function, which when translated means it’s a slipper clutch. This is a unique design – I’ve never before heard of a dry, single-plate slipper clutch – so I asked about it. The engineers looked at each other, smiled, and replied they could not yet talk about it, though they did confirm it is a mechanical system. Gone for analysis… right.

 

[Adrian R]

The R18 employs a dry clutch. The trans/gearbox is lubricated with multi-viscosity gear oil.

 

[Mr. Efficiency]

The bike has a dry clutch, so no worries there. I do use a specific JASO2 15w50 just sos during warranty noone can peep about it. I get mine from liquimoly in Germany via amazon.