What oil in my Big Red 200?

[hondajas]

What kind of oil should I run in the engine in my '83 Big Red 200? I'm pretty sure 10-40 is the best, that's what it says in the manual. But what kind. One guy said not to run automotive oil, so what else is there, is that true? I found some oil at Canadian Tire, it's 10-40, ATV four stroke oil, the back of the bottle says it's got very good defence on viscosity breakdown, good wet-clutch protection. Is this stuff any good, how about Castrol, do they make anything for 4 strokes. In the middle of summer when it's hot like 35C, or 95F, is it smart to use 20-50 motorcycle oil, or is that too thick?

[Mobular]

Castrol bike oils very good. Stay with the 10-40. I also use regular auto oil in my beater trike, and haven't had any probs for 8 yrs now. Just make sure you stay away from enhanced, friction reducing oils. They'll cause the clutches to slip.