Motor Oil 650Seca

Hello,
I am sure the topic motor oil was discussed frequently in the past – unfortunately I can’t find the posts. I thought 20W50 oil is the oil to use for air cooled 4 stroke engines. Recently I read in one of the posts that somebody mentioned 10W30. I live in Colorado and temperatures are pretty often in the high 90’s. I would appreciate if somebody could make their recommendation what motor oil to use for the ’82 XJ650RJSeca.
Thank you … Mike

 

I have used 10w40, 20w40 and 20w50. I am currently running 20w40 IIRC castrol dino.

I don't really know - when I ran 10w30 the PO flipped out and insisted on only 20w50 yamalube.

I can't tell a difference from outside the engine - so I'll leave it for someone else to answer which is best.

Given the high tempature and infrequent low tempatures a heavier oil should be fine.

 

i would go a little heavier due to high temps, you shouldn't have a prob.

 

the way it was explained to me, as long as you're not heavily riding, normal 10w30 or 10w40 is okay, the main difference you'll feel is in the clutch, which likes it real thin. So the clutch behaves heavy with thicker oil. Not really an issue for most.