I've been using Mobil 1 15W50  in my 2.1 for many years now. I'm in a maritime climate, Pacific Northwest.

-Mark 

> On Sep 30, 2024, at 6:22 PM, Jeff Palmer <w.jeff.palmer@ICLOUD.COM> wrote:
> 
> I’ve been running synthetic in my 2.1 Boston Bob since I had it installed about 15 years ago. Before that in my old 1.9 I would run 20w/50 from spring to fall before it would get parked in the winter. Wondering what weight I should use for synthetic with temps ranging from about 15C (60F) to 35C (95F). I believe my garage has been using 15W/40 but wanted a third opinion :)
> 
> Thanks
> Jeff
> 85 Westfalia GL on engine #2
> Sent from my iPhone