Cylinder Head Assembly; Hydraulic Timing Chain Tensioner - Yamaha WaveRunner FX SHO Service Manual

GEN
INFO

Cylinder head assembly

The newly designed cylinder head has 4 valves per cylinder: 2 intake valves and 2 exhaust valves.
The shapes of the combustion chamber and piston have been designed to obtain the optimum com-
pression ratio. The valve lifter is a direct-acting type with a valve pad. The valve spring is a single
type.
1 Valve lifter
2 Valve pad
3 Valve spring

Hydraulic timing chain tensioner

A hydraulic timing chain tensioner has been adopted in order to ensure that the tension on timing
chain is maintained. When the engine is started and engine oil is supplied to the timing chain ten-
sioner, the structure of the tensioner ensures that the rod is maintained in the proper position.
1 Timing chain tensioner
È Fully extended rod position
É Fully retracted rod position
Feature and benefit
IN EX
È
1
2
3
5
4 Intake valve
5 Exhaust valve
1
É
1-19
1
2
3
4
E