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.

Gaskets, oil seals and o-rings


  1. Oil
  2. Lip
  3. Spring
  4. 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:

    Ignition circuit cut-off system
    The ignition circuit cut-off system (comprising the sidestand switch, clutch switch and neutral switch) has the following functions. It prevents starting when the transmission is in gear and the sidestand is up, but the clutch lever is not pulled. It prevents starting when the t ...

    Cleaning and lubricating the drive chain
    The drive chain must be cleaned and lubricated at the intervals specified in the periodic maintenance and lubrication chart, otherwise it will quickly wear out, especially when riding in dusty or wet areas. Service the drive chain as follows. NOTICE The drive chain must be lubricated ...

    Checking the ignition coil
    1. Check: Primary coil resistance Out of specification  Replace. a. Disconnect the ignition coil connectors from the ignition coil terminals. b. Connect the pocket tester ( × 1) to the ignition coil as shown. Positive tester probe red/white "1" Negative tester probe orange ...

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