I have always put MC specific oil in my bikes but for the first time I put Chevron Delo 15w40 in my DR350. I did this because both Chevron and Shell recommend their heavy duty diesel oils in motorcycles and they cost under $2 a quart. These oils have less polymers and all the zinc phosphorous that MC oil have for the most part. I think I will probably be putting in the same in my wifes TTR 125 and may use the Rotella synthetic 5w40 in my XR650R. I'm just not seeing the need to spend the money on MC oils to dump on short change intervals any more http://www.rotella.com/qa/answerresult.php?rowid=81 http://www.chevron.com/prodserv/nafl/auto/content/faq.shtm "My motorcycle owner's manual recommends against using an SJ passenger car motor oil. What product does Chevron have for my motorcycle? Due to the inclusion of fuel economy requirements in the API category SJ, many oils have been formulated to contain friction modifiers. In a motorcycle wet-clutch application, these additives cause clutch slip and power loss. Chevron Delo® 400 Multigrade SAE 15W-40 is our recommendation for motorcycle use. "