Originally Posted by SrTelemaster150

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You show me an air cooled, carbureted, 12:1 compression ratio 4-stroke engine, running on pump gas & I'll show you an engine that will detonate under load once it gets to operating temperature.


10.5:1 can be streetable IF the right cam specs keep cylinder pressure down until the revs climb. 12:1 in an air cooled engine W/O computer controlled electronic fuel injection & ignition on pump gas is just waiting to hammer the piston crowns.