there really is no "proper age" for an xr 70. but, most xr 70's are riden by 10-13 year olds.
about 45
No, its a 4 stroke.
54
5 hp
45 mph.
.6 liters
2.5 oz +/- 0.03
The carburetor is a 22 mm one.
102 km/h
I've heard it's about 50 mph.
105-110 on a good day