So I know this has been done before, but since I don't know all of the terminology I'm going to explain what I'm trying to accomplish. Right now I'm designing a go-kart and I want to mount the engine in the back. So there is a little piece of frame right behind the seat that I intended to mount it on. I then had the idea to make it so that the piece of frame was able to pivot up and down and I put the shocks/coil springs on the support bars. After running this idea by a friend he said it already existed on ATV quad bikes. After doing some research I found that it was a thing called an ATV rear swing arm. But since the engine is hard mounted and a chain is run to the rear axle which is mounted on the moveable piece, I would think the up and down movement would mess with the tension of the chain. Apparently an ATV quad bike copes with it somehow but I don't understand how

***I made a little 3D model of my frame so far that I can take a picture of if anybody is confused what I am asking, I just couldn't figure out how to post a picture with the question or if I even can***