Got this from Biketalk.com
Your numbers look weak, hope this helps.
With a warm engine, turn off the fuel from the tank, make sure the choke is off and the transmission is in neutral. Remove both
spark plugs and insert the gauge adapter in one spark plug location. Now, holding the throttle wide open, turn on the starter motor
and read the pressure indicated on the gauge. Then repeat the procedure on the other cylinder. The figures on the next page give
some idea as to the significance of different pressure readings. Also some gauges have a rubber tip instead of a screw in adaptor.
Either way, reading the static pressure of your engine should be fairly easy. Generally, higher static pressures mean more
torque at lower RPM ranges but the trade off is that above a certain point (around185 PSI) the risk of detonation enters the picture. What happens at higher RPM is less predictable and can’t be easily determined from a static pressure reading. What is important is that the cam timing, duration and compression ratio all be properly matched so that each compliments the others.
ENGINE TUNING INFORMATION
STATIC COMPRESSION AND ENGINE TUNING
When installing cams with high lifts and long durations, a few general observations are worth keeping in mind. Remember that additional cam duration can produce more usable power but too much duration may actually hurt overall performance. The problem of poor engine response begins when too much duration results in lower cylinder compression pressure (at low RPM) which in turn can reduce low RPM torque and power. Too much duration in a camshaft is not necessarily a good thing.
Static Compression Pressure Ranges and Engine Performance:
Less than 115 psi: poor low speed response, hard starting. Pistons and cams well not matched or worn rings, valves.
125 to 145 psi: OK for stock or modified street motors. On the lower end of the best range for a stock motor.
145 to 165 psi: OK for modified street motors. Static pressures in this range will be best for stock street motors.
165 to 180 psi: Marginal for large displacement street motors, possible hard starting, detonation and overheating.
Over 180 psi: These are high performance numbers. Street motors over 185 PSI may need compression release.
The above numbers are not absolute but the point is that static compression is important. Proper matching of cams and compression ratio will allow engines to be modified for more performance and still run smoothly in street engines.
Carlos
