9:1+
It should have a minimum of 70 psi.
Actually HP can only be estimated . he HP depends on a lot of factors about the motor.
A diesel engine requires at least a 20:1 compression ratio, or about double a gasoline engine. The PSI this translates to depends on the size of the cylinder. You will need to consult the manufacturer's service manual.
On a exmark lazer z e-series 250 cc motor
10:1 - 12:1 through that range is fine
250 cc does not correllate to HP. Little 250 CC bikes are the fastest class of motorcyles--turbocharged, 10,000 rpm, high compression fuel injection running nitromethane--yikes! The most efficient engines would be very tiny but have all the ups and extras. Different 250cc engines put out anything from 1-100 horsepower. Essentially, it depends on how the engine is designed and what its intended purpose is.
14:1 compression
A KTM 85 typically should have a compression ratio in the range of 160 to 180 psi (pounds per square inch) when measured with a compression tester. This level indicates a healthy engine and optimal performance. If the compression is significantly lower, it may suggest wear or damage in the engine components, requiring inspection or maintenance. Regular checks are essential to ensure the bike operates efficiently.
120psi
60 p.s.i.
Alot.