Yamaha YZ125 2009, Owner'S Service Manual

Page: 107 / 234

4-24
CYLINDER HEAD, CYLINDER AND PISTON
Do not use a sharp instrument. Avoid scratch-
ing the aluminum.
INSTALLING THE POWER VALVE
1. Install:
• Power valve 1 "1"
• Power valve 2 "2"
• Bolt (power valve) "3"
Install the power valve at cut-away faced "a" for
down side.
2. Install:
• Spring "1"
• Link lever "2"
• Collar "3"
• Valve shaft "4"
• Valve holder "5"
• Bolt (link lever) "6"
• Install the spring to the link lever, and then to
the cylinder.
• Install the spring with its stopper portion "a"
facing inward.
• Apply the lithium soap base grease on the oil
seal lip.
3. Install:
• Thrust plate "1"
• Screw (thrust plate) "2"
4. Check:
• Power valve smooth movement
Unsmooth movement
→
Repair or replace.
5. Install:
• Gasket (power valve cover) "1"
• Power valve cover "2"
• Screw (power valve cover) "3"
• YPVS breather hose "4"
• Install the power valve cover so that the arrow
mark "a" faces upward.
• Install the clamp of the YPVS breather hose
with its opening portion "b" facing backward.
Bolt (power valve):
8 Nm (0.8 m•kg, 5.8 ft•lb)
Bolt (link lever):
4 Nm (0.4 m•kg, 2.9 ft•lb)
Screw (thrust plate):
4 Nm (0.4 m•kg, 2.9 ft•lb)
Screw (power valve cover):
5 Nm (0.5 m•kg, 3.6 ft•lb)