Yamaha YZF-R125 Service Manual: Electric starter

Installing the generator

1. Install: Woodruff key Generator rotor Washer Generator rotor nut NOTE: Clean the tapered portion of the crankshaft and the generator rotor hub. When installing the generator ro ...

Checking the starter motor

1. Check: Commutator Dirt Clean with 600 grit sandpaper. 2. Measure: Commutator diameter "a" Out of specification Replace the starter motor. 3. Measure: Mica under ...

Other materials:

Changing the coolant
1. Remove: Lower side cowlings Refer to "GENERAL CHASSIS" on page 4-1. 2. Remove: Radiator cap "1" WARNINGA hot radiator is under pressure. Therefore, do not remove the radiator cap when the engine is hot. Scalding hot fluid and steam may be blown out, which c ...

Outline of the fi system
The main function of a fuel supply system is to provide fuel to the combustion chamber at the optimum air-fuel ratio in accordance with the engine operating conditions and the atmospheric temperature. In the conventional carburetor system, the air-fuel ratio of the mixture that is supplied t ...

Starting failures
Engine 1. Cylinder and cylinder head - Loose spark plug - Loose cylinder head or cylinder - Damaged cylinder head gasket - Damaged cylinder gasket - Worn or damaged cylinder - Incorrect valve clearance - Improperly sealed valve - Incorrect valve-to-valve-seat contact - Incorrect valve timi ...