metallic 'slapping' noise

[Arnie]

Most likely culprit is the starter chain.  Don't worry about it.

Arnie

[RichBaker]

I bought my '90 with 2300 miles on her... The clutch rattled (still does), the cams rattled (still do) and I had various other unsettling noises, all at idle.  Part of it was a low idle, 900 rpm. Raised it to 1k rpm and most of the noises went away.... The cams, clutch and one other (can't remember now what) still rattle, but I've learned to appreciate the music she makes.