We never sold your model here in the USA so I have no information on it. The part looks like the position finger spring, also known as the rotary hook holder spring. It connects on the black position finger however that's all I know about it. Unfortunately we no longer have either the complete position finger or just the spring available. We sold our machines that used this part back in the 1970's and early 1980's. Riccar Japan who made these machine went bankrupt back in 1984 so the parts supply has dried up. Unfortunately I have no diagrams or photos to send you to show the placement of this spring. We are not the original Riccar company that sold these machines and we're are not in the sewing machine business so my knowledge is somewhat limited. Sorry we can't help</pre>