I knew Honda ndustrial engine, but didn't have a number.
I think the cylinders are their own, but they used to be V dub.
Carb is a Chinese S&S clone of dubious quality.
Ignition CDIs are from the Czech Republic and are potted, so no getting into them.
The bigger engines have blown oil filters, and Verner is recommending 20-50, I think. I'm still running Phillips 20/65, but the Aprillia oil filter is on the 3s is *very* robust.
That's all I have at the moment.