Whatever it is get it. People put knobbies on all kinds of stuff. But the XT is a 4 stroke single. 2 valve motor about the same motor as the SR500 and TT500. TX500 also known as the XS500 some years is a 2cyl DOHC 4 valve twin. Some earlier years would crack the head between the valves. The later years were good. They all looked cool.
Well, I'm a little biased on this topic, I've been racing an XT500 for 10 years. It's a great platform for a few things. Great road racer or Cafe bike. Great flattracker (with the right mods). Ok woods bike or dual purpose bike. The thing is, it's a 35 year old design, so if you compare it or race it against modern stuff, you'll have your work cut out for you, but as a vintage/amateur/period bike, it's hard to beat.
Tons of high perf stuff available to wake up that engine without turning it into a grenade. I love mine. If I had to sell all my bikes but one, or dump 'em in the ocean, whatever, I'd keep my XT.
If that's the bike for sale in the picture it looks like it's a $2500 -$3500 bike, depending on mods and stuff that I can't see. Spares?
I endurance raced one in about 83 or so. We had a KZ650 front wheel and forks on it. It went pretty good and crashed really well. Do you have a complete RZ350 front end? It might bolt right on.
If the price is right you should grab it up.
Last summer I planned to go to an estate auction and steal the XT that was on it thinking no one there would know what it was. The day of I spaced it a little bit and got there just in time to see the guy that had driven from Ill(min two hrs) and paid $1300 for it loading it in his truck. Swoop it if you can get it cheap.
I know where there's one sitting, but it's blown up, dissassembled, parts missing.