1. Remove the air filter.
2. Disconnect the cooling system steam outlet hose from the cylinder head cover.
3. Disconnect the crankcase ventilation hose from the cylinder head cover.
4. Remove a cover of the gauge distributor of ignition and disconnect wires from spark plugs.
5. Remove the cylinder head cover together with the ignition wire bundle and the ignition distributor cover.
6. Turn out spark plugs.
7. Turning the crankshaft clockwise with a key on the pulley mounting bolt, set the camshaft to a position in which the cams corresponding to one of the cylinders will be directed in the opposite direction from the rocker arms.
8. Check the clearance with a feeler gauge on both valves between the end face of the ball adjusting screw and the valve stem. When doing this, make sure that the adjusting screw is in the correct position with respect to the valve stem.
Clearances in the valve drive mechanism, mm: the normal clearance between the end of the adjusting screw and the valve stem, measured with a feeler gauge, is 0.15 mm on a cold engine for intake valves and 0.20 mm for exhaust valves, and on a hot engine, respectively, 0.30 and 0.35 mm.
9. If abnormal, adjust the clearance by turning the adjusting screw by loosening the locknut.
10. After adjustment, tighten the locknut and check the gap, then adjust the gap for the remaining valves in the order of the cylinders (1—3—4—2).
11. After adjustment, reinstall the cylinder head cover after checking the condition of the gasket. Screw in the spark plugs, attach the ignition wire harness, install the ignition distributor cap and air filter, attach the hoses.