We set the camshaft to the position corresponding to the end of the compression stroke of the 4th cylinder (see Adjustment of thermal gaps in the valve mechanism of the carburetor engine).
Loosen the cap nut on the chain tensioner (see Adjusting the tension of the camshaft drive chain of the carburetor engine).
To loosen the tension on the chain..
... resting with the mounting blade against the tensioner shoe, squeeze the tensioner rod and fix it by tightening the cap nut (Radiator hose removed for clarity).
Removal of the camshaft sprocket with chain and camshaft bearing housing is similar to the operations shown on the injection engine, with the exception of the work to disconnect the oil supply frame to the hydraulic supports (see Removal of a camshaft and levers of a drive of valves of an injection engine).
To remove the valve actuator lever..
... raise the lever, freeing it from the spring, and remove it.
Remove the lever spring.
Similarly, remove the drive levers of other valves.
Install springs and levers in reverse order. For further assembly, see Removal of a camshaft and levers of a drive of valves of an injection engine.
Adjusting chain tension (see Adjusting the tension of the camshaft drive chain of the carburetor engine) and thermal gaps in the valve mechanism (see Adjustment of thermal gaps in the valve mechanism of the carburetor engine).