Yamaha YZF-R125 Service Manual: Gaskets, oil seals and o-rings
1. When overhauling the engine, replace all gaskets, seals and O-rings. All gasket surfaces, oil seal lips and O-rings must be cleaned.
2. During reassembly, properly oil all mating parts and bearings and lubricate the oil seal lips with grease.
- Oil
- Lip
- Spring
- Grease
Replacement parts
Use only genuine Yamaha parts for all replacements.
Use oil and grease recommended by
Yamaha for all lubrication jobs. Other brands
may be similar in function and appearance, but
inferior in qua ...
Lock washers/plates and cotter pins
After removal, replace all lock washers/plates
"1" and cotter pins. After the bolt or nut has been
tightened to specification, bend the lock tabs
along a flat of the bolt or nut.
...
Other materials:
Removing the cylinder head
1. Align:
"I" mark "a" on the generator rotor
(with the stationary pointer "b" on the generator
cover)
a. Turn the crankshaft counterclockwise.
b. When the piston is at TDC on the compression
stroke, align the "I" mark "c" on the camshaft
sprocket with the mark "d" on the
cylinder h ...
Troubleshooting charts
Starting problems or poor engine performance
Starting problems or poor engine performance
Engine overheating
WARNING
Do not remove the radiator cap when the engine and radiator are hot.
Scalding hot fluid and steam may be
blown out under pressure, which could cause serious injury. Be ...
Throttle position sensor
1. Check:
Throttle position sensor
a. Connect the digital circuit tester to the terminals
of the throttle body sensor assembly
coupler as shown.
Positive tester probe →
gray/red terminal "1"
Negative tester probe →
gray/black terminal "2"
b. Measure the throttle pos ...