Hi Folks:
Over on the Cafe Husky forum, there was a pretty detailed discussion of oil and what kind of oil is actually best for a bike. It takes some time to read through this string of pages, but I know a heck of a lot more about oil than I did before. I've changed oil to Mobile 1 0-40 in our Huskies and now the brand new KTM's - have also changed to Stainless Steel oil filters. I know KTM recommends a 10-60 premium brand, but based on what I learned from this thread, a 10 weight is most likely too thick for start up - too much wear- and the 60 doesn't really do you any good at operating temperatures - having thinner oil at the same pressure means you are pumping a a greater volume and volume is what provides protection to moving parts and carries away heat.
Pretty interesting stuff for sure. Mobile 1 0-40 is about $25 for a 5 QT jug at Walmart.
http://www.cafehusky.com/threads/what-kind-of-oil-should-i-use-and-how-much.31911/