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Old 04-16-2009, 06:28 AM   #2
forchetto   forchetto is offline
 
Join Date: Jul 2008
Location: Gijon, Asturias,Northern Spain
Posts: 396
My Qingqi QM200GY (qlink XF200) with a CR of 9.4:1 has a permissible compression pressure of 139 to 199 psi. Yours with a slighly higher CR and only 125 psi seems below the limits.

Try repeating the compression test after putting a spoonful of oil down the plug hole. If it increases significantly it means the rings or bore are worn.
The oil forms a temporary seal around the rings and bore.

No change means valves are not seating correctly, either due to the clearances being too tight or burned valve seats.

Make sure the engine is warm and throttle is fully open while you carry out this test.

A quick figure for a reasonable compression figure for any engine can be calculated thus:

(CR x AP)+AP= compression pressure in PSI.

Where CR is the compression ratio
AP is normal atmospheric pressure (taken as 14.7 psi at sea level)

For yours this would be (9.5x14.7)+14.7= 154.35 PSI
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