OS FS 40 Surpass - Testrun with new bearings.

[@blahfaselalex]

Much smoother with new bearings

[@ChrisGauvin-i4f]

Huge difference with new bearings. I have os fs 48 im rebuilding. You inspired me to change them. Strong work. Keep it up. You are good at engines are you going to place this one in a bird?

[@tjuan7]

Nice break-in stand. Did you make it or buy it?

[@VintageTechFan]

It's a PSP stand, unfortunately they stopped making them quite suddenly. I got it (slightly) used from eBay.

[@earlyhemibill]

Can these motors be run inverted? I ask because I had an OS 1.20 twin and the instructions said not to run inverted.

[@VintageTechFan]

In principle, yes, but you may have to heat the glowplug in idle for maximum reliability. For the 120 twin (I think its the Gemini?) its because of the position of the crankcase vent. Oil may pool up in the crankcase instead of being pushed out through the camshaft case. 1