People love to ask and answer questions about what's the best oil to use in a motorcycle engine and the best lubricant, and how to apply it, for a motorcycle chain.
You get all sorts of opinions.
Some folks think it doesn't matter what brand of oil you use and that is doesn't need to be specifically formulated for a motorcycle. I tend to think there's some happy median (medium or something). Harley recommends diesel engine oil if you can't find the secret formula HD brand oil. Diesels run hot and go long distances between oil changes, so the oil for those engines has to be pretty good stuff.
The economics of trucking make the price for diesel engine oils competitive, unlike motorcycle oil where people can afford and are willing to pay 10 dollars for a quart of oil - because it's all discretionary spending to begin with unless it's your only vehicle - which is unlikely.
Interesting that if you're driving a semi-truck you can get service at Peterbilt including - oil (up to 44 quarts), oil filter(s), fuel filter, water filter and chassis lube for $179.95, and there are people who claim a Harley dealer wanted $225.00 to change oil or $191.00 if you supply the oil (4 qts). For that price it's probably a good idea to buy a screwdriver and a manual unless you don't like getting your hands dirty or are wrench challenged.
I only recently discovered that motorcycle forums have almost as many threads on chain lube as engine oil...
Some people like to remove chains from motorcycles and boil them in kerosene and then bake them in the oven to get a nice coating of grease - those would be your single motorcycle riders with a lot of time on their hands, who have older bikes that have a master link in the chain. Recommended interval for drive chain lubrication is every 200 miles and if it's wet/dirty on the road you may need to do it more often - so the boil and bake probably isn't very practical.
Some people use 3 in 1 oil or WD-40 on their chain. Some people think you should use a lubricant that says it's for a motorcycle chain (I'm with them).
Some people don't think you ever need to oil a chain - they must of never ridden a bicycle with a dry chain and realized how much easier it is to pedal when the chain is oiled.
I don't have any answers when it comes to oil for motorcycles but this guy seems to know what he's talking about when it comes to All About Motor Oil.
I've been using Mobil V-Twin 20W-50 synthetic oil in my Sportster and Shell Rotella Diesel Engine Oil 15W-40 in the Kaw. I used some super cheap Safeway brand before the Rotella. From what I've read that isn't a problem, as long as you change your oil frequently - which I was planning anyway. I was using the Safeway oil to make sure I had the right amount of oil in the crankcase and as a pre-drain oil before I put in something better a few days later when I did my first oil and filter change on the Kaw.
Rotella is around 14 bucks a gallon and Mobil 1 is 10 something a quart, at Autozone, which is about 7 blocks from my house - which plays into my decision to use those brands. Both the HD and the Kawasaki use a little less than a gallon of oil for an oil change and the recommended oil change is every 5000 miles on the Harley and every 3000 miles on the Kawasaki.