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Bf75 compression test

dstrat1

New member
"Guys, my clymer manual shows

"Guys, my clymer manual shows honda 75 compression as being 190 to 228....The engine has a compression ratio of 8.9/1....Is this a missprint? What should the results of a compression test be?"
 
"Pressure value when checked w

"Pressure value when checked with a gauge and compression ratio are two seperate things. Compression red from a gauge is the capability of the pinton/ring/cylinder to build pressure along with valve opening/seating, and compression ratio is only a volume ratio when piston is at TDC and BDC. 8.9 to 1 ratio is not = to 8.9 x 14.7 psi (ambient pressure). This is just a ratio, just indicative."
 
"So it might be possible, and

"So it might be possible, and most likely it is, that 190-228 PSI is the pressure limits the engine cylinders should achieve during a compression check."
 
"still, after a second thought

"still, after a second thought, above values look a tad high for such engine power/displacement...."
 
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