Re: are they 80cc
The 80cc designation is a marketing ploy used by the engine manufacturers and kit suppliers. They include the combustion chamber into the equation which isn't the correct way to calculate engine displacement. The cylinder bore and the piston stroke, multiplied by the number of cylinders is the only true way to determine displacement. When you buy a so called 80cc engine you are actually getting a 66cc.
Many engine kit suppliers use the 80cc number because it works well with search engines when people are looking for motorized bicycle kits. Be aware that there are a few sellers who will advertise their engines as "true 80cc". It just ain't so.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"