This subject has come up many times :? So I'm copying and pasting
I have learned a lot about oils in my experience and I have also taken courses on oil. I have seen many tests done on oil and here is what I have found out; you cannot compare regular petroleum based oil with synthetic oil, it is not a fair comparison! Synthetic oil is head and shoulders above regular oil. Its like comparing a 500 indy with an RX-1, not even close. Synthetic is that much better. The Yamalube 5W-30 is a pretty good oil, it is a blend of synthetic and petroleum based oil. I personally have been using Mobil1 over the past ten years. One of the many reasons is that I seen it tested in a Honda V65 motorcycle and it is known that a motorcycle of this type is the harshest environment for motor oil, reason being the same oil is used in the engine, transmission, and wet clutch. And in this particular test the Mobil 1 15W-50 came out on top! It was compared with Castrol Syntec 5W- 50, Castrol GTX 20W-50, HondaLube 20W-50 (also a blend), and Spectro4 20W-50. And that is the order in which they perfomed in Viscosity breakdown, relative density, ability to suspend particles, coating metal surfaces (cold startup) and ability to withstand heat.
I have seen engines run with Mobil 1 for 200,000 miles torn down with virtually no wear! I can tell you many more stories but it would go on for too long! I will be switching to Mobil 1 15W-50 in my Warrior after break in. This particular oil was originally designed for high performance, high revving cars, and hard working pick up trucks. But it works extremely well in motorcycle and ATV engines, and like I said I have been using it for ten years in various motorcycle's and ATV's. I change it once a year, because Synthetic does not break down as rapidly as petroleum based oils, another advantage. If you are using Synthetic and you lose your oil pump, or water pump, your engine has a much better chance of surviving, because everything internal is coated, I've seen many tests done to demonstrate this advantage also. Now don't be fooled by the numbers 15W-50 these designations are only used so the consumer would not be confused. I have used this oil for years in ATV's with no problems starting in the winter, even when it is well below zero. The 15W-50 will pour down to-49 degrees and on the other end you can literally cook it in a frying pan and it will withstand it! If they had to label this oil according to what it was capable of it would read like this; 0W-100 and nobody would understand that. I'm not trying to promote Mobil 1, I'm sure the Amsoil is an excellent oil also, so take your pick! I'm just sharing my experience and knowledge on the subject. I know one thing for sure; if you use Synthetic oil your engine will last much longer and it is the best thing you can do for both cold weather starting and hot weather running.
Bob
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