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mcnugget22
02-19-2008, 12:26 PM
What should the compression test be on a stock 400ex?
Got Boost
02-19-2008, 12:36 PM
120psi I believe.
JOEX
02-19-2008, 01:06 PM
100-128 psi
hornetgod13
02-19-2008, 02:52 PM
Like JOEX said 100 to 128 psi WARM. Run the motor first, than install the compression tester. Hold the throttle wide open and crank the motor until the pressure is maxed out. Shouldn't take more than 3 to 5 seconds of cranking.