Help getting electric gates to 180 degrees

Hi there guys i have picked up some ditec underground gate motors i am wanting to get one of the gate motors to open to 180 degrees so that one of my gates will fold right back , some manufacturers sell a 180 degree kit like what i have attached in the image however these kits seem to be very expensive for such basic parts... can i ask if i supply some images of my gate motor would any one on here be able to fabricate some thing for me :-D i would buy the part direct but they dont make one for my ditec cubic 30 but its really just 2 sprockets and a chain

As you can see on the images i need were my finger is cut down and a sprocket welded and were my thumb is cut through and a sprocket sandwiched between and welded back up

 

Should be able to purchase a similar sprocket and chain either from sources like McMaster Carr and Motion Industries, and then weld an arm to the larger sprocket.