Withdrawal
1. Using a special tool to compress the valve springs (09222-28000, 09222-28100), remove the cracker. Next, remove the upper valve spring plate, valve spring, lower plate and valve.
Note. Save all the parts in the order in which they are to be installed in their original positions.
2. Use pliers to remove the sealing cap. Do not reuse it.
Examination
Valves
1. Using a wire brush, thoroughly clean the valve.
2. Check each valve for wear, damage or breakage to the head and stem in area B. Repair or correct as necessary.
If end A of the rod is worn out, resurface it if necessary. This direction should be minimal. Restore also the surface of the working chamfer of the valve. If the valve head height is less than the specified limit, replace the valve.
Valve springs
1. Check the length of the spring in the assembled state and its extension. If it exceeds the allowable limits, replace the spring.
2. Check the parallelism of the ends of each spring. If it exceeds the specified limits, replace the spring.
Valve springs:
- Height - 21.6 kg / 35 mm
- Load - 45.1 kg / 27.2 mm
- Edge parallelism is 1.5°or less
Valve bushings
Check clearance between valve stem and bushing. If it exceeds the limits, replace the valve bushing with the next size bushing.
Gap between valve stem and bushing.
Nominal size:
- Inlet valve - 0.03-0.06 mm
- Exhaust valve - 0.05-0.08 mm
Size limit:
- Inlet valve - 0.1 mm
- Exhaust valve - 0.15 mm
Valve seat
Check the valve seat for signs of overheating and proper contact with the valve face. Repair or replace the valve seat if necessary. Before repairing the seat, inspect the valve liner for wear. If the bushing is worn, replace it and then repair the seat. Repair the valve seat using a valve seat grinder or cutter.
Valve seat replacement procedure
1. An over-worn valve seat should be replaced at normal temperature after cutting away most of the seat wall using a valve seat grinder as shown.
2. After removing the seat, use a reamer or cutter to machine the seat hole. Processing is carried out to the size indicated in the table.
3. Heat the cylinder head to about 250°C and press in the oversized seat. The oversized seat must be at normal room temperature before installation. After installing a new seat, treat its surface. Valve bushing replacement procedure.
The procedure for replacing the valve sleeve, as well as installing the valves, is the same as for engines with a single camshaft (see the relevant section earlier in this chapter).