REMOVAL AND INSTALLATION

Removal steps <<A>> >>G<< 1. Cylinder head bolt assembly >>F<< 2. Cylinder head assembly >>F<< 3. Cylinder head gasket <<B>> >>E<< 4. Valve spring retainer lock 5. Valve spring retainer >>D<< 6. Inlet valve spring >>D<< 7. Exhaust valve spring 8. Inlet valve 9. Exhaust valve <<C>> >>C<< 10. Inlet valve stem seal <<C>> >>C<< 11. Exhaust valve stem seal >>C<< 12. Valve spring seat 13. Inlet valve guide 14. Exhaust valve guide 15. Inlet valve seat 16. Exhaust valve seat >>B<< 17. Stud >>A<< 18. Stud 19. Cylinder head

Use the following special tools to compress the valve spring. Remove the valve spring retainer lock. Valve spring compressor (MD998735) Retainer holder D (MB992283) note Store removed parts such as valves and springs with tags describing cylinder No. and installed position for reassembly.

Use special tool valve stem seal pliers (MB992085) to nip the base of the stem seal (where the outside diameter is larger) securely, and remove it by twisting it to the left and right.

1. caution Valve stem seal for inlet valves and for exhaust valves are different. Be sure to install the correct ones. The valve stem seal must not be reused. Do not damage the tappet wall during assembly. Be sure to use a special tool to install the valve stem seal. Poor installation causes oil loss via valve guides. If oil is not applied, the valve stem seal may rise to the surface after it is press fitted. Apply a small amount of engine oil to the press-fit part and lip part of the new valve stem seal. 2.Use a special tool to install the valve stem seal, obeying the following procedures.

3.Special tool valve stem seal installer adjustable (MB992922) is composed of the components shown in the illustration. 1: Chuck 2: Sleeve 3: Rock nut (small) 4: Outer pipe 5: Rock nut (large) 6: Guide pin (5.9) 7: Guide pin (4.9) 8: Cap 9: Guide pin (5.4)

4.Adjust the inside chuck diameter, obeying the following procedures. (1) Install the sleeve to the chuck as shown in the illustration. (2) Install the shoulder of the valve stem seal to the chuck, aligning with the outer circumference line of the chuck as shown in the illustration. (3) Turn the sleeve to wring the chuck. (4) Stop the sleeve at the position where you can easily remove the valve stem seal by hand. (5) Use the (small) rock nut to fix the sleeve.

5.Adjust the stem seal insertion length [L (L1)], obeying the following procedures. (1) The position, in which the end face of the outer pipe is aligned with the outer circumference line of the chuck, is 0 mm of the insertion length. Insert the chuck and the sleeve into the outer pipe to fit the nut as shown in the illustration. (2) Turn the chuck to adjust the valve stem seal insertion length. note The insertion length can change by 1 mm per the chuck turn. To easily know how many times the chuck is turned, put the mark at the position shown in the illustration. (3) Use a vernier caliper to measure the checkpoint (L1) of the insertion length shown in the illustration. Check the insertion length. Inlet (L1): 18.6 mm Exhaust (L1): 19.8 mm (4) Use the (large) rock nut to fix the sleeve.

6.Install the cap to the guide pin (5.9). 7.Install the guide pin (5.9) as shown in the illustration. 8.Apply the engine oil to the valve stem seal to set the chuck. 9.Install the valve spring seat.

10.Use the plastic hammer to insert the valve stem seal.

Install the inlet valve spring so that its painted side faces the rocker arm side. note The exhaust valve spring can be fitted either way up.

1.If the cylinder gasket is only replaced, check the notch shown in the illustration to select the gasket that is the same in size.

2.If either one of the cylinder block, piston, connecting rod and crankshaft is replaced, select again the gasket according to the following procedures: (1) Keeping each piston at top dead centre, measure the amount of projection from the block top at the 8 places shown in the illustration. Always measure it on the centre line of the crankshaft. (2) Use the average of the 8 measurements to select the gasket size (A, B or C) according to the table shown below. If either one of the measurements at 8 places exceeds the specified maximum projection, use the gasket that is one size larger. Type by size Average piston projection mm Maximum piston projection mm Fitted thickness mm A (1 notch) 0.511 - 0.564 0.615 1.30 ± 0.05 B (2 notch) 0.564 - 0.618 0.668 1.35 ± 0.05 C (3 notch) 0.618 - 0.671 - 1.40 ± 0.05 note If the projection amount of piston exceeds the allowable value, replace the piston, connecting rod, crankshaft or cylinder block to check it again.

3. caution Do not allow any foreign materials get into the coolant passages, oil passages and cylinder. Wipe off the sealant and grease on the top surface of the cylinder block and the bottom surface of the cylinder head, and degrease the surface where the sealant is applied. 4. Apply the sealant to the top surface of the cylinder block as shown. Specified sealant: ThreeBond 1217G or equivalent note Install the cylinder head gasket immediately after the application of sealant. Apply the sealant so that its bead is centred at the chamfered cylinder block surface and the sealant groove. 5.Install the cylinder head gasket to the cylinder block. 6.Apply the sealant to the top surface of the cylinder head gasket as shown. Specified sealant: ThreeBond 1217G or equivalent note Install the cylinder head assembly immediately after the application of sealant. Apply the sealant so that the centre of its bead reaches the edge of the cylinder head gasket. 7. caution After the installation, until a sufficient period of time (one hour or more) elapses, do not apply the engine oil or water to the sealant application area or start the engine. Install the cylinder head assembly.

3.Use special tool 12.7sq. torx bit socket (MB992916) to tighten the cylinder head bolts by the following procedure (plastic region angular tightening method). (1) Tighten the cylinder head bolts to the specified torque in the order shown in the figure in two or three steps. Tightening torque: 50 ± 2 N·m (2) caution When the tightening angle is smaller than the specified tightening angle, the appropriate tightening capacity cannot be secured. When the tightening angle is larger than the specified tightening angle, remove the bolt to start from the beginning again according to the procedure. Apply paint marks to the head of cylinder head bolt and the cylinder head. (3) Tighten the cylinder head bolt in a 90° according to the tightening order. (4) Tighten the cylinder head bolt in a 90° according to the tightening order. Check that the paint mark on the cylinder head bolt and the paint mark on the cylinder head are on a linear line. (5) Loosen the cylinder head bolt fully. (6) Tighten the cylinder head bolt to the specified torque again in the order shown in the figure. Tightening torque: 50 ± 2 N·m (7) Tighten the cylinder head bolt in a 90° according to the tightening order. (8) Tighten the cylinder head bolt in a 90° according to the tightening order. (9) Tighten the cylinder head bolt in a 90° according to the tightening order. Check that the paint mark on the cylinder head bolt and the paint mark on the cylinder head are at an angle of 270°.