Castrol 5W50 100% synthetic has an incredible viscosity range that should handle every conceivable climate condition. Does it have any bad additives that would mess up the wet clutch? It looks like the perfect lubricant. The synthetics I see most on this board are Mobil 1 15W50 and Amsoil 20W50. Thanks.

By G. Mann on Sunday, October 28, 2001 - 11:10 am:

I haven't looked at the markings on the container of Castrol 5W50 synthetic. There is a circle on the back of oil containers that has rating information printed in it. If the bottom of the circle says "energy efficient" I understand that this would have some friction modifiers which might not be the best for your Gold Wing. There are lots of people around here who know more about oil than I do, however. Maybe someone can explain this.

I do know that the Mobil 1 works well in the transmission and clutch on my bike. It is also readily available and is not marked "Energy Efficient". I wonder if the 5 weight component of the Castrol might not be just a bit light? I' don't know. Let's see what someone else has to say. This question comes up all of the time for sure.

G. Mann
'94 SE

By Dennis Firth on Sunday, October 28, 2001 - 04:05 pm:

Tom I run 5w50 Syntec in all my motors other than the snowblower which runs 0w30, yes for you folks in the warm sunny south, there is 0 weight oil.
Some don't like the broad range because of the molecule chain size but it works for me.
Even the old Briggs and Scrap Iron lawnmower likes the 5w50.
Lots of new vehicles going to 5w20, closer tolerances and reduced wear at cold startup along with fuel economy are the factors. As a matter of fact customers bringing their vehicles in to the dealer complaining of reduced fuel economy are being quizzed about their last oil change.
Remember that a multiweight oil "behaves like" a 5 weight at a certain temp and then " behaves like" a heavier weight as oil temperature increases.
My biggest reason for using it is that Costco sells it cheap.

By JimGwing on Sunday, October 28, 2001 - 04:35 pm:

i would use mobil one instead, i had the castrol 5w50 in my wifes mustang, and it does not flow as well in cold weather, the lifters would rattle till the oil pumped up to them..J.D.

By George W. Russell on Sunday, October 28, 2001 - 08:11 pm:

Hey Jim: 5 weight oil flows about as good as water. Not much else will flow as well. I've used Syntec for a few years now, no problems with it. Also have been using Castrol products for about 47 years for motorcycles, they work great! Not many products around will have that kind of devotion to bikes! George'83GLI Isn't it great to be alive ®

By Dennis Firth on Sunday, October 28, 2001 - 09:22 pm:

Jim you might want to check the oil filter you are using... if side mounted some brands drain back and then have to fill before the oil gets to the rest of the engine... just a thought....