Connecting Rods, Pistons & Cylinder Sleeves

1.DESCRIPTION

The I -section connecting rods are forged steel and carry a bronze bush at the small end for installation of the piston pins. The big end is mounted on the crankshaft over steel backed alloy replaceable bearing inserts. The big end bearing caps for each connecting rod are matched fit and the matching parts are numbered to ensure correct assembly.

2.CONNECTING ROD AND PISTON ASSEMBLY

a)REMOVAL :

1)Remove the cylinder head.

2)Remove the carbon ridge at the top of each sleeve.

3)Remove all the bolts securing the oil pan to the crankcase and pull out the oil pan. Remove the gasket from the crankcase and discard it.

4)Remove the bolt securing the oil pump to the crankcase and carefully withdraw the oil pump. Take care not to damage the teeth in the pinion gear.

5)Take off connecting rod bearing caps (2-1) with bearings and lift out pistons with connecting rods, by pushing up and out of the sleeve.

6)Replace inserts (9-2) in bearing caps (8-2) on connecting rods to prevent mixing up.

7)With long-nose pliers remove piston pin retainer springs by squeezing pronged ends, fig. 4.

NOTE: If the cylinder sleeve has been worn so that there is a ridge in the sleeve at the upper end of the piston travel, this must be removed before the piston is withdrawn, to prevent damage to the ring lands and rings during removal of piston.

3.INSPECTION AND REPAIRS :

NOTE: i)Do not hold the piston in a vice. ii)Always service/change the piston and piston pin as a set. iii)It is advisable that, whenever the piston and the connecting rod assembly is removed from the sleeve new piston rings be installed while re-assembling. a)Check the piston ring grooves for wear, using new ring and feeler gauges (Fig. 5). See specifications for acceptable clearance. b)Check the pistons for seizure or/and overheating marks.