Well, I'll try to help out from a technical point of view on the black art that is oil.
First, I would ask that you think twice about using non specified oil in your motorcycle because unless you have an air cooled Harley with a separate tranny or a dry clutch bike like a lot of Ducati’s, your motorcycle has two things being serviced by the oil that a car/truck engine doesn’t. Having a smaller sump, higher rpm, high compression (for a N/A gas engine) along with the tranny and clutch really puts extra demands on motorcycle oil.
Firstly, weight (10w40, 20w50) should be determined by the motorcycle manufacturer. They engineered it and have a pretty good idea of what it needs for given operating conditions. The “w” stands for winter and essentially, tells us that a 10w40 acts like a 10 weight oil when cold and has the properties of 40 weight oil in service. This is done by additive packages blended in to provide a “best of both worlds” compromise.
Normally, you would not see straight weight oil in an engine, more likely, fork oil. The thing to note is that these additives are less stable than a straight weight but you want the flexibility of multi grade in an engine so you deal with it. Now, other additives are added to oils based on their needs such as:
-Anti-foam agents – If you introduce air into the oil and froth it you lose the ability to support the load.
-Detergents – These help minimize sludge build up.
-EP (extreme pressure) – Sulfur or similar may be added to create a chemical reaction under pressure to protect surfaces. Obviously this benefit also causes acids to form so bases may be added if used. Nothing in life is free.
-AW (anti wear) – These could be corrosion inhibitors like zinc.
Then you have synthetics which are man-made oils that have a desirable molecule structure allowing wide range benefits. Synthetics can do what conventional oil can with fewer additives and also have benefits like great cold pour point and higher boiling points.
Now, if the oil is API graded as the manufacturer specs and you use it then no problem and perhaps two differently labeled bottles will actually contain the same thing but you can’t know that without testing.
Tribology is the science and engineering of interacting surfaces in relative motion. If you ask most tribologists for the pinnacle of oil engineering companies they will vote Exxon Mobil. From my experience as an ICML certified person who worked with oil analysis from the prospective of a maintenance/reliability engineer I can honestly say I almost always buy Mobil 1 products. Mobil does not always win every test I have seen but I’ve never seen one where they perform poorly.
My recommendations are as follows:
-Use a weight and spec listed for your conditions in your owner’s manual.
-Use bike specific oil. Safe bet they have an additive package intended for the application.
-Use synthetic oil. Beyond cost, this is a win/win.
-Don’t make your own additive package (adding slick 50 and crap) because it is unlikely you have the knowledge to know what you need. Mess up your ratios and how bad would a mixed cake taste?
-Stay with Mobil, Castrol, Motul etc… Do you really believe a small company has the resources to better the big guys? Maybe in certain conditions but not likely overall, if they were that good and had something special, the big guys would buy them out like Microsoft does with software developers.
-Change your oil. No matter how good it is, dirt is the enemy. This is within reason of course.
-Break in on non-synthetic oil unless advised otherwise by manufacturers. Change oil and filter at least once before 200 miles to ensure any casting dirt and initial grime is out of the engine. I usually do it around 100 miles and it really is cheap insurance.
-Pre oil your filter before you put it on. Running the engine while the pump pressurizes and fills an empty filter is not smart.
-Verify your oil level. Not too high or too low, just right.
-Warm up your engine. Stuff expands with heat so tolerances get where they should be before riding hard.
Hope that helps you guys and was brief enough to have you all stay awake.
