I was given an older Pantera. I took the engine and put it in an Honda Odessey frame. My son was riding today and it suddenly quit. I noticed the seal behind the clutch had come out.

Do I need to seperate the crank halves to replace this seal? I haven't taken the clutch off yet. My 700 Wildcat EFI has seals with a ridge on them that fits a groove in the crankcase.
Any help will be greatly appreciated.