Contents: Removal ↓ Installation ↓
Cylinder head: 1 - valve; 2 - nut (tightening torque for stud M10 - 30 Nm (3.0 kgfm), for stud M8 - 25 Nm (2.5 kgfm)). Observe the tightening sequence; 3 - valve stem cuff (replace only for intake valves); 4 - valve spring (the end with the smaller pitch - to the cylinder head); 5 - valve crackers (adjust with increased thermal clearance);6 - Hexagonal nut M8 (copper plated; tightening torque 25 Nm (2.5 kgfm)); 7 - support (installed with the cut facing upwards); 8 - valve rocker (check for wear); 9 - spring washer; 10 - thrust washer; 11 - valve guide bushing;12 - push rod (check for bending between two base elements; runout - max. 0.3 mm); 13 - protective tube (pre-tension - seam up); 14 - sealing ring (replace); 15 - cylinder head
Important! If only the valve lifter protective tube is damaged or the tube sealing ring needs to be replaced, there is no need to remove the cylinder head, as detachable protective tubes are available.
Removal
Remove the engine (see section "Removal and installation the engine").
Remove the intake manifold together with the carburetor (see section "Removal and installation the carburetor").
Remove the fan.
Remove the muffler (see chapter "Exhaust system").
Remove the engine covers.
Flush the engine with gasoline, especially in the area of the cylinder heads.
Caution! Avoid open flames as there is a risk of fire!
Bend down the cover mounting bracket using a large screwdriver.
Remove the lid (wash before installation).
Unscrew the 2 M8 hex nuts securing the valve rocker arm shaft.
Remove the axle together with the valve rocker arms. Remove the sealing rings under both support posts (replace them with new ones when installing).
Remove the push rods.
Remove the 8 bolts (see location. in the "Installation" subsection) and remove them together with the washers.
Caution! If it is necessary to remove only the cylinder head without removing the cylinder and piston, the cylinder must be secured against falling out with suitable wire loops or a metal clamp.
Note: To make it easier to remove the cylinder head in this case, you can use a rubber hammer.
Remove the cylinder head and valve lifter protective tube.
Installation
Attention! When installing heads with modified cylinder mounts, 1 mm thick compensating rings are installed between the cylinder and the head.
Before assembly, check the head for cracks in the combustion chambers and exhaust channels. In addition, check the sealing surfaces of the cylinder bases and the intake manifold flange. Replace the damaged head.
Check the threaded portion of the spark plugs and studs for damage. Damaged or stripped threads on spark plugs can be repaired using a wire spiral thread insert.
When disassembling the rocker arm axles, check all parts for wear. Replace damaged parts and assemble according to the pictures.
Check the valve lifter rods for bending (the runout should not exceed 0.3 mm). To do this, the barbell is placed on a flat surface (for example, on glass) and check the runout using flat feeler gauges.
If scratches are found on the working surfaces of the valve rocker arms and supports, they can be removed using fine-grained sandpaper. For this purpose, sandpaper is placed on a flat surface.
Before installation, stretch the old protective tubes of the tappets to the nominal size.
The pushrod protective tubes are pre-tensioned. The dimension "a" is about 180 mm for the Kafer 1200 engine, and about 190 mm for the Kafer 1300 engine.
Carefully install the cylinder head. When installing the pushrod protective tube, ensure that the sealing rings are carefully seated between the crankcase and the protective tube, as well as between the latter and the cylinder head.
Caution! Use new sealing rings for the pushrod protective tubes.
Turn the protective tubes of the pushers so that the seam is directed upwards.
Place washers under the cylinder head bolts and tighten them by hand.
Note: Bolts under the head cover (1, 2, 3, 4) install, after having lubricated it with D3 sealant.
Caution! Use a torque wrench to tighten the cylinder head bolts.
Lightly tighten the cylinder head bolts in the sequence shown to a torque of 10 Nm (1 kgfm).
Finally tighten the cylinder head bolts in the sequence shown in the figure. M8 bolts are tightened to a torque of 25 Nm (2.5 kgfm), and M10 bolts to a torque of 30 Nm (3.0 kgfm).
Insert the pushrods, place new sealing rings on both studs and install them on the valve lever axle studs.
Attention! Pay attention to the cuts on the support posts (indicated by arrows) were on top, and their beveled edges were directed outward.
Caution! Use only new hex nuts (M8). Tighten them to a torque of 25 Nm (2.5 kgfm).
Adjust the valve clearances (see section "Adjusting valve clearances").
Install the valve cover with a new gasket.
Secure the engine covers and cooling fan.
Install the muffler.
Install the intake manifold and carburetor.
Install the engine.
Perform a test drive and check for oil leaks from the valve cover.
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