Disassembly
1. Turn out the spark plugs with a wrench (suitable special tool).
2. Remove the valve lifters.
Mark the locations and stack the components in order without mixing them.
3. Take out the crackers.
Compress the valve spring with tool, attachment and adapter (special tool: KV10116200) (A). Remove the crackers with a finger magnet (IN).
Attention: When performing this operation, do not damage the holes for the valve lifters.
4. Remove the valve spring cup and valve spring.
5. Push the valve stem towards the combustion chamber and remove the valve.
Mark the locations and stack the components in order without mixing them.
Mark the valves for reassembly.
6. Remove the valve gland with a puller (special tool: KV10107902) (A).
7. Remove the valve spring seat.
8. If valve seat needs to be replaced, see below «Valve seat replacement».
9. If the valve guide needs to be replaced, see below «Valve Guide Replacement».
Assembly
1. If the valve guide was removed, install it. See below «Valve Guide Replacement».
2. If the valve seat was removed, install it. See below «Valve seat replacement».
3. Press in the valve seal.
Press the valve seal with a punch (special tool; KV10115600) (A) according to the dimensions shown in the figure.
Height «H»: 13.2-13.8mm
4. Install the valve spring seat.
5. Install the valve.
Install larger valves on the intake side.
6. Install valve spring.
Note: It can be installed in any direction.
7. Establish a plate of a valvate spring.
8. Install crackers.
Compress the valve spring with tool, attachment and adapter (special tool: KV10116200) (A). Place crackers with a finger magnet (IN).
Attention: When performing this operation, do not damage the holes for the valve lifters.
After installing the valve components, lightly tap the tip of the valve stem with a plastic mallet to ensure proper seating.
9. Install the valve lifter.
10. Screw in the spark plug with a wrench (suitable special tool).
Check after disassembly
Valve dimensions
Check the dimensions of all valves.
If the dimensions are out of specification, replace the valve.
Guide bush gap
Valve stem diameter
Measure the valve stem diameter with a micrometer.
| Standard | Inlet | 4.965-4.980 mm |
| Release | 4.955-4.970 mm |
Valve guide inner diameter
Measure the inside diameter of the valve guide with a bore gauge.
| Standard | Intake and Exhaust | 5.000-5.018 mm |
Valve guide clearance
(Valve guide clearance) = (valve guide inner diameter) - (valve stem diameter)
| Standard | Inlet | 0.020-0.053 mm |
| Release | 0.030-0.063 mm | |
| limit | Inlet | 0.1 mm |
| Release | 0.1 mm |
If the value obtained exceeds the limit, replace the valve and/or valve guide.
Valve Guide Replacement
If the valve guide is removed, replace it with an oversized guide (by 0.2 mm).
1. Remove the valve guide by heating the cylinder head to 110-130°C by immersing it in hot oil.
2. Press out the valve guide using a press [with a force of 20 kN (2 tons)] or knock out with a hammer and drift (suitable special tool).
Caution: The cylinder head is hot. Wear protective clothing to avoid burns while working.
3. Ream the valve guide hole in the cylinder head using a reamer (suitable special tool).
Valve guide hole diameter (repair size): Inlet and outlet: 9.175-9.196 mm.
4. Heat the cylinder head to 110-130°C by immersing it in hot oil.
5. With a punch (suitable special tool) press in the valve guide (1) from the camshaft side, referring to the dimensions shown.
Attention: Cylinder head (2) hot. Wear protective clothing to avoid burns while working.
6. Using a sweep (using a special tool) Finish the surface of the valve guide.
| Standard | Inlet and outlet | 5000-5.018 mm |
Valve seat contact pattern
Perform this check, making sure that the dimensions of the valve guides and the valves themselves are within specifications.
Apply red lead (or lead white) on the contact surface of the valve seat and check the fit of the valve to the seat.
Make sure that the red lead imprint shows up around the circumference without breaks.
Otherwise, achieve the required degree of valve fit by regrinding and check again. If the contact surface is still unsatisfactory even after rechecking, replace the valve seat.
Valve seat replacement
If the valve seat is removed, replace it with an oversized valve seat (by 0.5 mm).
1. Drill out the old seat until it breaks. Drilling must not continue deeper than the bottom of the seat recess in the cylinder head. For this purpose, put a drilling depth gauge on the drill.
Caution: Do not scratch the cylinder head by overdrilling.
2. Ream out the notch in the cylinder head for the oversize valve seat.
Increased size (by 0.5 mm).
Intake: 31.900-31.916 mm
Outlet: 26.400-26.416 mm
Ream in concentric circles towards the center of the valve guide. This will ensure proper seating of the valve seat.
3. Heat the cylinder head to 110-130°C by immersing it in hot oil.
4. Cool the valve seats well with dry ice. Press the valve seats into the cylinder head.
Attention:
- Do not touch chilled saddles with bare hands.
- The cylinder head is hot. Wear protective clothing to avoid burns while working.
5. Finish the seat to the required dimensions by milling or grinding with a suitable special tool.
Attention: When processing a surface with a milling cutter, grasp the handle with both hands. Then press the cutter against the contact surface around the entire circumference and mill in single passes. If the tool is pressed unevenly or with a break, the valve seat may take a stepped shape.
6. Lappe the valve with grinding paste.
7. Recheck valve seat.
Valve spring squareness
Attach a square to the valve spring and rotate the spring. Measure the maximum gap between the top of the spring and the square.
Limit: 1.8mm
If the clearance exceeds the limit, replace the valve spring.
Valve Spring Dimensions and Compression Force
Check valve spring compression at standard spring height.
| Standard | |
| Length unloaded | 42.26 mm |
| Height after installation | 32.40 mm |
| Load after installation | 136-154 N (13.9-15.7 kg) |
| Open Valve Height | 23.96 mm |
| Open valve load | 262-296 N (26.7-30.2 kg) |
If the specified values are out of specification, replace the valve spring.