I looked on line and see some outrageous prices for that link. Do you know the width of the chain? Most bikes of that era used a 219 chain which came in various different pin thickness and side plate thickness, so they used different connecting links. We used chains from an SR500 in most of our motors. I have no idea of the length or your chain (number of links or of the chain dimensions, but see if you can find an alternative chain. Looks like your bike has a heavy duty 219 chain from crank to idler and lighter 219 chain to the cams.
Or buy a used chain from ebay.