Quiz: how well do you know your Yamaha YZF-R125?

18 questions. After each answer you get a short explanation and a link to the manual page that covers it in detail.

What is the longest you should crank the YZF-R125 engine with the start switch on a single attempt?
10 seconds. Do not crank for more than 10 seconds at a time. If it does not start, release the switch and wait a few seconds. Short attempts preserve the battery. Starting the engine

What is the specified drive chain slack on the YZF-R125?
30.0-40.0 mm. Slack is 30.0-40.0 mm, measured at the tightest point of the chain with no weight on the bike. Check it before each ride. Drive chain slack

Why must you avoid water getting into the brake fluid reservoir when refilling?
It lowers the boiling point and may cause vapor lock. Water significantly lowers the boiling point of brake fluid and could cause vapor lock. Also never mix different fluid types, and wipe up spills quickly as they damage paint and plastic. Checking the brake fluid level

When preparing the R125 for long-term storage, what goes into the spark plug bore to protect the cylinder?
A teaspoonful of engine oil. Pour a teaspoonful of engine oil in, then turn the engine over with the starter to coat the cylinder wall. Ground the plug electrodes while doing so to avoid sparks. Storage

What should you do if the coolant temperature warning light comes on while riding?
Stop the engine immediately and let it cool. The light signals overheating, and you must not keep running the engine. On models with a radiator fan, it switches on and off automatically based on coolant temperature. Indicator and warning lights

During the first 500 km of break-in, which engine speed should you avoid for prolonged periods?
Above 6000 r/min. For 0-500 km avoid prolonged running above 6000 r/min, and let the engine cool 5-10 minutes after every hour. Between 500 and 1000 km the limit rises to 8000 r/min. Engine break-in

At what front brake pad lining thickness must the pads be replaced as a set on the R125?
Less than 0.8 mm. Front pads under 0.8 mm (or damaged) need replacing as a set by a dealer. Rear pads have a different limit: 1 mm. Checking the front and rear brake pads

How much engine oil does the YZF-R125 take when the oil filter element is replaced?
1.00 L. With filter element replacement it takes 1.00 L; without it, 0.95 L. The oil should be API SG or higher and JASO MA. Specifications

Why should riders avoid loose-fitting clothes on a motorcycle?
They can catch on levers, footrests or wheels. Loose clothing can snag and cause injury or a crash. Protective clothing should also cover legs, ankles and feet because engine and exhaust get very hot. Protective apparel

Where is the vehicle identification number of the R125 stamped?
On the steering head pipe. The VIN is stamped into the steering head pipe, while the model label is on the frame under the rider seat. The key number is on the key tag. Identification numbers

How do you check the steering head for play on the R125?
Rock the front fork gently with the front wheel raised. Raise the front wheel, grasp the bottom of the fork legs and rock gently; binding or looseness means adjustment. Never overtighten the lower ring nut. Checking and adjusting the steering head

What should you use to clean plastic parts like cowlings and windshields on the R125?
Soft cloth or sponge with water. Use a soft clean cloth or sponge with water, or at most diluted mild detergent rinsed off thoroughly. Harsh chemicals damage plastic. Care

How should the thermostat be oriented when installing it on the R125?
Breather hole facing up. Install the thermostat with its breather hole facing up. Handle the coolant temperature sensor with care and replace it if dropped. Installing the thermostat

How are turn signal and tail/brake light bulbs removed from their sockets?
Push and turn counterclockwise. These bayonet bulbs are pushed in and turned counterclockwise. Meter and indicator bulbs are instead carefully pulled out. Types of bulbs

If a connector is found damp during an electrical check, what is the remedy?
Dry it with an air blower. Moisture is dried with an air blower; rust or stains are cleaned by connecting and disconnecting several times. A contact revitalizer works as a quick remedy. Checking the connections

When checking the timing chain tensioner, what indicates it must be replaced?
Rough movement of the rod. After winding the rod clockwise and releasing it, it must come out smoothly. Rough movement, cracks or damage mean replacement. Checking the timing chain tensioner

How should multi-fastener assemblies be tightened to avoid warpage?
Crisscross pattern in progressive stages. Tighten in a crisscross pattern and progressive stages up to the specified torque. Torque values assume clean, dry threads and room-temperature parts. General tightening torque specifications

If vertical scratches are found on the cylinder wall of the R125, what is required?
Replace the cylinder, and the piston and rings as a set. Vertical scratches mean replacing the cylinder, plus piston and piston rings as a set. Piston skirt diameter is measured 5.0 mm from the bottom edge. Checking the cylinder and piston

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