Best Oil Weight.

[Racinkc1]

I think the owners manual was calling for 10w 30 but I cant find that weight on motosport outlet. It looks like they are mostly selling 10w 40 for bikes. I usually ride in cooler climates at a little elevation. I dont believe in synthetic oils, just another gimmick.... I also like Belray lubricants because NASA uses them. I was looking at that Belray Mineral 4T 10w 40 EXL 4 stroke engine oil. Any other recommendations?

 

[grayracer513]

10w-30 is only suitable if temperatures typically reach lows down to 10 ℉ and no higher than 70 at any time.  Not very useful for very many people.

 

10w-40 is OK down to the same lows, but applicable to temps ranging up to 110 ℉.  20w-40 will service the same max temp range, but isn't suitable below 50 ℉ ambient temperatures. 

 

There is little or no benefit to a 50 weight (such as a 20w-50) unless temperatures are almost always above 90 ℉ and you're doing a lot of slower riding in technical areas that could lead to high engine heat along with relatively high ambient temps, so a 10w or 20w-40 will do just fine for most people almost all the time.