I'd say the kx 125
Matters of opinion have easily-dissolved answers.
The 1991 Kawasaki KX125 produces approximately 30 horsepower (bhp). This two-stroke motocross bike is known for its lightweight and agile performance, making it popular among riders during its era. The power output contributes to its strong acceleration and capability on the track.
gas
kx 125 is better because KTM 125 or any ktm snap so go with kx 125
about 65 to 70
The dirty, rusty trails on the train track were to damaged for the train.
Trail: For the trail it will help you find your way and to know that its a safe trail and other people been on it. No Trail: It helps you see things that you never seen before but you might get lost because maybe its not a trail because its dangerous Trail: good thing is you can find your way better. bad thing is when its foggy you can't see much. Non-Trail: sometimes you wont find your way unless you know it well. a good thing is when its foggy you can see better in the trees!
32:1 is the standard oil mixture on the kx125 a little more oil is way better then too little!
The top speed for a Kawasaki KX125 is about 70 miles per hour. That would be the speed with a 150 pound rider.
65-75
KX125 bike can be bought in vehicle stores, such as Velo Street. It may be available in a local bike shop that does not have a globally famous worldwide link.