Not sure how loose you define tech, but mine would be my motorcyle, a 1981 Yamaha XS400 that my grandfather gifted me. It’s certainly feeling it’s age, so it requires a lot more effort on my end to keep running than most bikes made this century. It’s not made for modern highway speeds, it’s not happy when I try, so I keep it off the interstate, 50 and under. That said, when the weather’s good, I’ve never had a carbeurated engine start so easily, and it’s a joy to ride!
Honestly mostly just age related stuff. It spent most of its life leaning against a barn wall, so even though it had low miles when I got it, everything was feeling the age and a lot of maintenance items came due very suddenly all at once. The muffler basically desintigrated one day as I was driving it, had to patch a hole on one side and replace the other entirely. Then it was seals, just about everywhere except the pistons (thankfully), so I’ve had just about everything except the actual engine block out at some point or another.
Shockingly the fuel system is rock solid after replacing all the rubber bits in the carbeurators. Sometimes I have to use the kick starter in colder weather, but usually I can pop the choke out and the electric start gets it going in 2 cranks.