Since K bikes have a dry clutch, you do not need to buy special motorcycle oils or worry about additives. It is perfectly acceptable to use plain old automotive motor oil.

 

From the owner's manuals:

 

From a notice put out by BMW in 2007:

 

FWIW, I generally use one of the following oils on a 10,000 mile change interval:

• Mobil 1 15W-50 Synthetic (generally least expensive in the five quart jug from Wal-Mart)

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• Shell Rotella T6 5W-40 Synthetic (also available at Wal-Mart but not that expensive elsewhere)

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Low Mile Engines: For bikes with 20,000 or less miles, use a good regular motor oil like Castrol 20W-50 in order to let the rings seat properly.

 

© 2013 Drake Smith - Please do not use or reproduce this elsewhere.  Feel free to link to it though.