I think that it can be important to note what the numbers of oil mean. 5-30
or 15-50. The first number is the weight of the oil when cold. the second
number is the weight of the oil when HOT. Most oild get up to operating
tempetures very quickly. It is important to have the same high temperture
number as recomended. the lower number helps provide lubrication at start up.
Especially in cold weather. There are some questions about wide ranging oil
such as 5-50; they use additives to make a "thin" oil to stand up in heat
(instead of thining out even more). These additives will wear out faster than
your oil. Try and stay away from oils that have a "shift" that are more than
15-20 points.

If you are a real oil nut use cheap oil and change it every 1500 miles or so.
synthetic is great but still builds with crud like any other oil. ( I use
mobile 1 syn. 15-50 and change every 3000)

My understanding of it

Todd T
84 & 76 Westy
washington DC