I also used to think you could run just about any motor oil in our motorcycles without worrying about the consequences. That may no longer be the case as EPA mandates over the last several years have forced refiners to significantly reformulate many of the products we've depended on for years. Here's a little more info than I provided earlier.

What brought this to light for many was Ford's decision to recommend against the use of motor oils meeting some of the latest API standards in any of their diesel engines. It's unusual for a major manufacturer to take such a position. I'm sure the engineers behind the recommendation took some heat as there were obvious political ramifications.

Basically here's what happened. Significant increases in wear were observed when Ford tested diesel engines using oils that met both the latest API gasoline (SN) and diesel (CK-4) standards. Ford attributed the increased wear to a significant reduction in ZDDP, a phosphorus/zinc anti-wear compound found in all motor oils. So after the new standards were introduced in late 2016, Ford issued a position statement which said motor oil meeting the new CK-4/SN standards should not be used in any Ford diesel. They later approved some higher viscosity (40+) CK-4 oils for use. I was in Walmart the other day and noticed that Motorcraft diesel oils, which are formulated to meet the older CJ-4 standard, state 'CONTAINS MORE THAN 1000 PPM PHOSPHORUS FOR BETTER WEAR PROTECTION' right on the front label.

This is important information for motorcyclists. MC specific oils have usually contained fairly high levels of ZDDP. Many of us have used diesel oils (such as Shell Rotella) as a cost effective alternative because of their similar anti-wear properties. With these new API standards it probably isn't a bad idea to check out the specs of whatever oil you've been using. Even Mobil 1 4T (10W-40 MC oil) has had its ZDDP content reduced since 2016.

It's also worth mentioning that lower viscosity (30 and below) automotive oils have had drastically reduced ZDDP content for several years, and may not be a good choice for motorcycle engines.