On Sun, 11 Dec 2016 15:58:18 -0800 (PST), Christopher Tidy
wrote:

Am Freitag, 9. Dezember 2016 23:39:51 UTC+1 schrieb David Billington:

Chris,

I would guess that the small engine you took apart with rolling
element bearings was a 2 stroke, that's pretty standard whereas a 4
stroke would be plain bearing.

Actually, no. It was a 4-stroke JAP air-cooled engine and had taper-roller main bearings. Not such a new engine, I suppose, but much newer than the other engines I was working on at the time. It started me wondering if the change was part of a pattern.

Chris
A lot of "industrial duty" 4 strokes have rolling element bearings on
thePTO end - some balls, some rollers. A few have them on both ends.