Detach the big-end caps with the lower bearing shells (arrowed)

shells, from the crankpins (see illustration),then detach the connecting rods, complete with the upper bearing shells, from the crankpins.

5 Ensure the camchain is free to be lifted out of the engine and lift the crankshaft with the camchain attached out of the upper crankcase half, taking care not to dislodge the main bearing shells. Push each piston/connecting rod assembly down the cylinder and remove it, making sure the connecting rod does not mark the cylinder bore (see illustration).To ease withdrawal of the piston/connecting rod assembly, remove any ridge of carbon built up on the top of each cylinder bore. If there is a pronounced wear ridge, remove it using a ridge reamer. Caution: Do not try to remove the piston/connecting rod assemblies from the bottom of the cylinder bore. The piston will

22.5a Remove the piston and connecting rod from the top end of the cylinder

nof pass the crankcase main bearing webs. If the piston is pulled right to the bottom of the bore the oil control ring will expand and lock the piston in position. If this happens it is likely the ring will be broken. Install the relevant bearing shells (if removed), bearing cap and nuts on each connecting rod assembly so that they are all kept together as a matched set (see illustration). 6Do not remove the bolts from the connecting rods. Note:It is not necessary to renew the big-end bolts when the connecting rods are removed. If, for any reason, the bolts have to be renewed, drive the old bolts out of the rods by tapping gently with a hammer. Under no circumstances twist the bolts while they are in the rods. Because the bolts have knurled shanks and are a tight fit in the rods, take care to align the bolt heads with the machined insets in the rod shoulders before

B Keep the piston and rod (A), big-end

Cap (B) and cap nuts (C) together as an

Assembly

pressing them into place (see illustrations).

7Remove the pistons from the connecting
rods (see Section 23).

Inspection

8 Check the connecting rods for cracks and other obvious damage. Check that the oil hole in the connecting rod big-end is clear (see illustration).

9 Apply clean engine oil to the piston pin, insert it into the connecting rod small-end and check for any freeplay between the two (see illustration).Measure the pin external diameter and the small-end bore diameter, then calculate the difference to obtain the small-end-to-piston pin clearance (see illustrations).Compare the result to the

22.6a Ensure the new bolt head (A) is correctly aligned with the inset (B)...

Date: 2016-01-14; view: 621