Note: The cam chain tensioners and guide blades can be removed with the engine in the frame.
Cam chain tensioner
Removal
1. Remove the valve cover (see Section 8). The cam chain tensioner is located in the back of the cam chain tunnel. Note the position of the rubber cushion behind the top of the tensioner.
2. Follow Steps 2 to 5 in Section 9.
3. Slip the sprocket off its boss on the camshaft.
Note: Do not disengage the cam chain from the sprocket or the valve timing will have to be reset (see Section 9).
Caution: Do not rotate either the camshaft or the crankshaft whilst the cam chain sprocket is displaced as damage could occur if a valve contacts a piston.
4. Unscrew the two bolts securing the cam chain tensioner and withdraw it from the cylinder head (see illustrations). Also remove the rubber cushion, noting which way up it fits (see illustration).
11.4a. Unscrew the bolts (arrowed)...
11.4b ...then withdraw the tensioner...
11.4c ...and remove the rubber cushion, noting how it fits
Inspection
5. Examine the sliding surface of the tensioner for wear or damage, and replace it if necessary.
6. Check the tensioner spring for damage or a loss of tension, and replace it if necessary.
Installation
7. Fit the tensioner into the back of the cam chain tunnel in the cylinder head, making sure the base is correctly seated in its slot. Fit the rubber cushion with its widest end uppermost behind the top of the tensioner (see illustration 11.4c). The top of the cushion sits flush with the top of the cylinder head. Make sure the sealing washers on the tensioner mounting bolts are in good condition, and replace them with new ones if necessary (see illustration). Apply a suitable non permanent thread locking compound to the tensioner bolts and tighten them to the torque setting specified at the beginning of the Chapter.
11.7. Use new sealing washers on the tensioner bolts if necessary
8. Mount the cam chain and sprocket onto the boss on the camshaft. Apply a suitable nonpermanent thread locking compound to one camshaft sprocket bolt, then install it in the exposed hole at the top of the sprocket and tighten it to the specified torque setting, using a socket on the alternator bolt to stop the engine from rotating if necessary (see illustrations 9.27). Rotate the crankshaft anticlockwise 360° to reveal the other sprocket bolt hole, then threadlock the bolt and tighten it to the specified torque setting. Again rotate the crankshaft anti-clockwise 360° to bring it back to TDC on compression. Before proceeding further, check that everything aligns as described in Section 9. Step 2. If it doesn't, the valve timing will be inaccurate and the valves will contact the piston when the engine is turned over.
9. Follow Steps 30 to 35 in Section 9.
10. Install the valve cover (see Section 8).
11. Check the engine oil level and top up if necessary (see Chapter 1).
Cam chain guide blade
Removal
12. Remove the cylinder head (Section 12).
13. Lift the cam chain guide blade out of the front of the cam chain tunnel in the cylinder barrel, noting how it fits (see illustration).
11.13. Draw the guide blade out of the tunnel
Inspection
14. Examine the sliding surface of the guide blade for wear or damage, and replace It if necessary.
Installation
15. Install the guide blade into the front of the cam chain tunnel, making sure its base locates correctly in its seat, and the lugs near the top seat correctly in their slots (see illustration).
11.15. Make sure the lugs locate correctly in the cutouts (arrows)
16. Install the cylinder head (see Section 12).