Attention! To check compression, the engine must be warm and the battery fully charged.
To check the compression in the cylinders, you must first remove the fuel tank (see «Fuel tank - removal and installation») and disconnect the four low voltage wires from the ignition coils (see «Ignition coils - removal and installation»).
1. We turn out the candles of all cylinders.
2. We insert the tip of the compression gauge into the spark plug hole of the cylinder being checked and press it tightly to prevent gas breakthrough, or screw it in if the tip has a thread of a suitable diameter.
Fully open the throttle valves by turning the control handle towards you as far as it will go. We turn the crankshaft with a starter for a few seconds and measure the compression.
We sequentially carry out this operation for all four cylinders of the engine. For a serviceable engine, the compression value is 11-15 bar. The compression value in the cylinders should not differ by more than 1 bar.
Advice. If in one of the cylinders the compression value differs from the others by more than 1 bar, it is recommended to repeat the test by filling the cylinder with 5 cm3 of engine oil. If the compression normalizes, it is necessary to check the condition of the piston rings and the mirror of this cylinder, otherwise diagnostics of the valve mechanism are required (see «Cylinder head - checking and adjusting valve clearances», «Valves - removal and installation, lapping»). You should also check the condition of the cylinder head gasket.