At the last oil change (26K KM) on my 1150GS, we switched from dino oil to semi-synthetic. The manual and the mechanic (K. Yut, Dynamic Motors, BKK) specify 20-50 Semi-synthetic, but I have looked everywhere and only found 10-40 in semi-syn. Yut has advised that if I have to choose between topping up with 20-50 dino and 10-40 semi-syn, to go with the semi-syn, which I did today. I'd rather put the right thing in there - anyone seen 20-50 Semi-Synthetic for sale anywhere? Tks much.