Beat up 2 stroke 49CC scooter that belonged to my bother in law. My wife really wanted it after he passed, so we got it running and licensed. It's pretty beat up, but It gets around town just fine. 13,000 miles on odometer. It will do about 30mph (165 lbs) with me on it and almost 35 with my wife riding.
She uses it to ride up to the grocery store (10 blocks away) or to cruise around Emerson. We've taken it camping with us a few times, and explored Ponca State Park and around Chadron a few times. Her nieces and nephews love it as well.
Well, not exactly ecomods, but...
+2 stroke oil tank was damaged, so I removed it and mix the oil in with the gas
+New plug, wire, and coil
+rebuilt carb (pain the butt...CV carbs suck)
+toggle switch to kill the lights (battery only charges when it is ridden wide open)
+LED tail lights/turn signals
+larger tires, brakes, and new rear shock
+roller weight mod in transmission to increase top speed (hurt acceleration some) and new Yamalube
None. This thing could quickly become a money pit, and still only be usable in our little town. This thing would be deadly on the highway, and we live in pretty rural Nebraska.