There is no "synch speed" for a leaf shutter, it synchs at all speeds. Since you didn't specify, I'll assume it's in a Copal shutter. I don't recall if this has a selector for "X" or "M" synch, if it does have the selector set it to "X". If no selector, it will be "X" synch, and in either case it will synch at all speeds.

Where did you search online? I found this in about 8 seconds.