His motors are roughly the same bore/stroke as the Sachs that I have, and depending on quality of the parts, Russ could nail 8000 rpm... the piston speed isn't that bad, but the quality of the materials used come into play.
They used to rev the p_ss out of those Westbend motors... were they really better built than a Lawnboy motor? (I'm asking- I don't know!)
I haven't had a Lawnboy to disect yet, but from the pix I've seen, they seem to be a quality product.
We've got some great "don't see anyone for miles" roads close by, so safety isn't an issue. I plan on wringing out the LR v2 on one someday.
A kart on the street is a deathwish, might as well be invisible.
...and trusting my life to something I put together isn't!?!?