Since Tyrespinner asked, yes some people have bad things to say about Castrol. I can't be more specific because I don't remember the whole story, but on a Honda streetbike forum they were talking about some lawsuit against Castrol for something like falsly advertising their Syntec. I honestly didn't pay much attention, but all those guys were saying to avoid Castrol. Also, one of the guys said he talked with a Castrol tech who told him all their auto oils service factor SG or newer have the friction modifiers and should NOT be used with a wet clutch. For what it's worth, I used Amsoil motorcycle synthetic in my bike and use Amsoil injector oil in my quad (no longer a Sport400, now an Explorer 400 4x4).

 

Castrol GTX isn't synthetic and you talking about a different oil.

 

Actually, I looked on a bottle of Castrol GTX today and it clearly says it has "Anti-wear additives for a long engine life"...

So I'm going to stay away. I might try Yamalube or HP4 depending on the price.

Thanks