You can check it with a Timing Light. On the right side of engine cases,below where the 2 cylinders meet, is a large Allen screw. Remove that. Remove your timing cover, RH side of engine on gear cover. This will expose your Ign. plate. Hook the light to your front spark plug wire and point the light at the hole from the allen screw. Raise RPM's to at 2k., this advances your timing. You should see a Dot in the hole, pretty much centered. If it's not then loosen the 2 stand offs for the timing plate so you can rotate it to center, or within the opening. the Dot. You should see a slot to place a small screw driver to rotate the plate.
The timing plate may still be on with 2 Rivets and will have to be drilled out. They will have to be replaced or get a cover with holes for screws to screw into the stand offs. A service manual will really help you if you don't have one.
tourbox