Yamaha YZF-R125 Service Manual: Checking the camshaft sprocket and timing chain guide

Yamaha YZF-R125 Service Manual / Engine / Cylinder head / Checking the camshaft sprocket and timing chain guide

1. Check:

  • Camshaft sprocket More than 1/4 tooth wear "a" Replace
    the camshaft sprocket, timing chain and crankshaft as a set.

Checking the camshaft sprocket and timing chain guide


a. 1/4 tooth

b. Correct

1. Timing chain roller

2. Camshaft sprocket

2. Check:

Timing chain guide (exhaust side) Damage/wear Replace.


    Checking the cylinder head
    1. Eliminate: Combustion chamber carbon deposits (with a rounded scraper) NOTE: Do not use a sharp instrument to avoid damaging or scratching: Spark plug bore threads Valve seats ...

    Checking the timing chain tensioner
    1. Check: Timing chain tensioner Cracks/damage/rough movement Replace. a. Lightly press the timing chain tensioner rod into the timing chain tensioner housing by hand. NOTE: While pressing the ...

    Other materials:

    Intake air temperature sensor
    1. Check: Intake air temperature sensor resistance Out of specification Replace the throttle body. a. Connect the pocket tester ( × 1k) to the throttle body sensor assembly coupler as shown. Positive tester probe brown/white "1" Negative tester probe gray/black ...

    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 ...

    Introduction
    WARNINGDisc brake components rarely require disassembly. Therefore, always follow these preventive measures: Never disassemble brake components unless absolutely necessary. If any connection on the hydraulic brake system is disconnected, the entire brake sy ...

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