Can't resist stirring the pot - my Transcontinental Rider's Manual, on page 169, says: SAE 15W-50, API SJ / JASO MA2, BMW Motorrad recommends BMW Motorrad ADVANTEC Pro. Maximum of 0.5 L for a top up (between the lines in level glass) and 4.0 L for an oil change with a new filter. I use Penrite 4-Stroke motorcycle oil, 15W-50 - a fully mineral version (API SL, JASO MA2). Penrite MC-4ST 15W-50. Liquid gold, imho. I think BMW's ADVANTEC Pro is a semi-synthetic? So might need to get with the times and swap to a semi-synthetic?