I am looking for a source for OS parts. Specificly for an old OS 61 VF. I need to find a piston and liner for this engine. I have worn it out after many years of service. I have another VF but sure would hate to loose this one. Thanks for the help.

Have you considered parts interchangeability with the FX? The FX bore/stroke is 0.945" x 0.866" - just a shot in the dark. Fwiw, Tower lists a replacement FX piston and liner (OSMG4946) for $92.99

Good luck.

Mike

Tower hobbies is the importer for OS engines if they dont have it you are going to be out of luck unless someone out there has those parts lying around
Good luck
Brian

Unfortunately this was back when OS made engines that were worth a damn. LOL. They have changed the engines somewhat. I will measure but I don't think it will work. The VF is a rear exhaust engine.

Performance Specialties has what you are looking for. Henry Nelson manufactures the true ABC piston & sleeve assemblies for them. They stock a wide range of assemblies for popular old and new O.S engines as well as Y.S. 2-strokes. These are the same guys who import Y.S.

FWIW - the FX series of engine are totally different than the older O.S.'s. The new design has a shorter sleeve with a cylinder head that sits on top of the sleeve like modern Supertigres do. They won't interchange with SF and earlier engines.

I will check out performance specialists. I think I already looked there buit i will drop them aline. thanks. I will keep you guys updated.

Watch eBay, as there are almost always new old stock parts being auctioned there.

I chatted with performance specialists by email today. It turns out that piston and liner for the OS SFN 61 fits the old FSR engines and the piston for the RFN fits the VF series of engines. Performance specialists no longer makes these though. I did manage to order a new stock one from Tower though. I hope this helps anyone else in the same situation.