I had a similar issue on a slightly older Legacy steamer. Judging by the frequency/rapid pace of the sound, it's definitely coming from the area of the flywheel and could easily be a stray wire touching it as it rotates. In my case the flywheel was actually touching the chassis of the engine, which I figure came about as the result of shipping damage. It took some effort to create enough separation between the two parts to stop it happening.
Thanks. I have not taken it apart so shall see.