So I picked up my Honda GX-31 last week and just got a chance last night to fire it up for the first time. Oh my sweet lord, this engine speaks my language. Never in my life have I heard such a sweet sounding, smooth, mellow engine note. It idles right around 1900 RPM and spins up to 9800 RPM. The clutch starts to engage at 4000 RPM which is just a little before the torque peak. No pics of my engine yet, because I don't have internet at my new house yet, but I've been taking pictures of the modifications. Stock is 1.5 HP. I'm shooting for quite a bit more.