ORIGINAL: countilaw
I have several .61 SF, and the parts are getting harder and harder to find. Rings and bearings are plentiful, but to replace a sleeve, piston, rod, crank or a case are next to impossible find. And if you did find them the cost would be more than a new engine. The SF swings a large prop and preferrs a RPM in the 11 K area.
I would recommend a new engine like the Jett, Navorossi, YS or even Evolution .61 NX.
It would depend on the type of pattern plane you are looking to build or have.
Frank
Right Frank......
Like this one.
I have not run it yet but when I do you'll probably be able to hear it.
For the record....the model number of this engine is 206R61