Sticking shutter at around 1/60 is a common problem. I recently bought an FX-2 at a charity shop for 20 bucks. Mine stuck at any speed! Took off the winder and carefully ran some oil down the shaft, this improved things, but it can still stick at 1/60. It obviously needs a good service. Perhaps Yashica used an inferiour oil/grease than other makers when assembling it. ALL old cameras really need a good service. This costs money, assuming you can find someone who knows how to do it. There are no professional service manuals. But don't give up, these old 35 SLR's are great cameras. I use my collection for 'rough' shoots, motocross etc., as they are the only cameras that will work in the mud and dust, and during harsh winters. Digital sucks when it gets rough.
Big Sven
September 2010