your gonna need to compensate for both rpm and altitude if high..

75 seems low.. shop manual indicates 100psi -250rpm

 

above 100 psi is good .....

 

100 psi by the spec page in the manual. 7 kg/cm^2 In the tune -up section with the engine warm it calls for 85 PSI 6 kg/cm^2 @ 250 RPM.



Hopefully you were only turning over at say 200 RPM. In that case 75 PSI should be OK. According to the chart on page C-10 of the manual.

 

ewww! time to go to pettit and get a real compression test done.