I had a couple of 26" Jamis mountain bikes, Suntour components. Sold one to a friend, still have the other, chromoly steel frame, now w/Deore XT on it after I swapped that gruppo out from a Klein Attitude I bought new, spec'ed w/that. Next year, when the XTR gruppo was released, I had that installed, and put the Deore XT onto the Jamis.
The guy who started Jamis was an attorney in FL. He popularized the 'beach cruiser,' but also had high-end (for the times) MTB's like the Dakar.
A good fix on the snapped-off crank. As soon as I saw the crank, I knew it was an Ashtabula-style. Pretty-sure those are forged, not cast. Left-hand threads are distinguished by markings on the crank arm, on a 3-piece crank. It looks like this: III