Unreliable? None really, they all got me home. But some of them caused me grief when leaving home. My first; a Sears 106SS. Magneto powered, so my leg was the starter button. I abused the heck out of that thing, rebuilt it more times than I can count and still rode it all over the SE U.S.. I bought a few 4cyl Hondas searching for a bigger bike to cover more miles - began to dislike tinkering and got rid of them as fast as I could. No more UJMs for me! Right now, my cuss-bike is my Honda PS250 (BIG Ruckus). I wanted one when they first came out in '05, and found one at the right price about 7 years ago. Figured I'd tuck it into a corner of the garage and save it for my old age. That damn thing will drain a battery when trying to start it cold. Everything checks out, but it's just the most cold blooded bike I've ever had. HATE it - until it's running, then it's a fun little scooter.