amsoil 15/50 dominator , its what i use

i can agree to that but if the oil is a street legal oil it will not have some additives in it that oil a few years ago did have. This is the reason to go with a off road type of oil that does not need to meet the EPA regulations to be street legal.

15/40 in a gas motor?

filtration was great on both, the flow rate is the size of the holes for flow, much bigger on the R. I change oil every 25 hours, so far I am liking the Amsoil too.

X2, With Ao filters..

I wouldn't recommend running a motorcycle oil in your boat engine. Motor cycle oils have less friction modifiers for better clutch performance. Amsoil makes three different types of high Zinc content oil for harder working engines. The reason for the low Zinc in current automotive oils is that the Zinc causes the catalytic convertors to deteriorate. The Amsoil 15w40 Marine / Diesel oil is the lowest cost high zinc oil, then you have the Z-Rod famiy and then the Dominator racing oil. When choosing an oil please look for SAE standardized testing to compare them. I have never seen a test yet that showed that any brand was better then Amsoil, and I have looked. On another note WIX R series filters are 60 micron filters or should I say strainers. If you are looking for the best you can get and have room for a taller filter check out the Amsoil EA076, it's almost 2 quarts. My oil is so clean after 2 seasons that I hate to through it away.

v-twin oil is blended for harleys...the motor oil doesnt go in the clutch,and it is high in zinc (and vitamins)

I'm a Amsoil dealer too.

The 2 quart filter works great my oil still looks like new, put about 40+ hrs on it so far. I will do the same this fall when I winterize.

Works great, been running it for several years. I like it better than the 10/40 Marine oil.