I had one of these as a parts bike,the 72 was kind of an awkward time for Yamaha. kind of a hopped up enduro but still with some MX parts. When the 73/74's came out the 72 was forgotten so hardly anybody races a 72 in vintage MX.
Still be a cool and violent bike to get running. I sill have some center cases for one in the basement and some other small odds and ends. I have a pretty good crankshaft as well. Most any vintage 35mm Yamaha MX/enduro fork will go right on and look and feel the same,they can be real cheap on ebay.
Could be a 36mm fork but I dont think so.
Some bikes around at times