72cc usually gets to 30-40 but it all depends on the treatment of the bike
72cc, 52mm bore
The 4-speed Manual clutch Honda 70 (72cc) engine is rated at 5 hp.
You can try to look on line or you can try to find a manual book for it
That is 8.818 cups
That is 2.998 cups.
That is 3.086 cups.
That is 3.308 cups.
That is 1.48 cups
80 cups
That is 1.609 cups.
5.07 cups