the bmw oil from my dealers in san diego are blended and packaged from spectro oils america for bmw america. this time they gave me 20-50. 10-40 or 20-50 as long as it lubes. change it regularly alls good. if you see a diffrence go back. use motor cycle specific oil no issuses. they are probly blended from a hand full of companies. i intend to go spectro as i have used on the dirt bike. (xr400) for 12 years. my independent mechanic uses it. xracer. pick a brand and go ride. money wise some squable about a few dollars on oil but not on tires. that get changed at say 10k miles. i think some one here said im getting a head ache, me too. pic one and go ride. this is my first post.