2021 Yamaha YZ125X Specifications

Name: 2021 Yamaha YZ125X
Brand: Yamaha

No images available

Tap to enlarge

2021 Yamaha YZ125X Overview

The 2021 Yamaha YZ125X is an enduro / off-road motorcycle built around 125 cc of displacement. Under the tank sits a Single cylinder, two-stroke engine, a compression ratio of 8.8:1. The bore and stroke measures 54 x 54.5 mm. From a practical standpoint, the 2021 YZ125X tips the scales at 94.8 kg, carries a 8-litre fuel tank, offers a seat height of 975 mm and spans a 1455 mm wheelbase. Scroll down for the complete 2021 Yamaha YZ125X spec sheet covering every technical detail from suspension travel to tyre sizes.

2021 YZ125X - Pros & Cons

Strengths

Factory engineering: The 2021 Yamaha YZ125X represents Yamaha's engineering at the time, with a specification built around real-world usability.

Considerations

Carburetor fuelling: Carbureted engines need occasional jetting attention and can be reluctant in cold weather or at altitude compared to modern fuel-injected alternatives.
Tall seat height: The 975 mm seat height will challenge shorter riders - tiptoeing at low speeds is something to factor into your decision.

Owner Experiences & Common Issues

Carburetor maintenance

Carburetors on the 2021 Yamaha YZ125X benefit from a clean and re-jet if the bike has been stored, run on stale fuel, or modified with an aftermarket exhaust. Owners frequently mention that fresh jets and float needle clips transforms throttle response from flat to crisp.

YZ125X - Buying & Maintenance Guide

What to check before buying

When inspecting a used 2021 Yamaha YZ125X, start with the basics: check the service book for oil change frequency, inspect the chain and sprockets for wear, and look for oil seepage around the engine casings and rocker covers. A cold start test is invaluable - a well-maintained YZ125X should fire up cleanly and settle to a smooth idle within a few seconds.

Oil and filter changes

Regular oil changes are the single most important maintenance task on any YZ125X. Stick to the manufacturer's interval - typically every 6,000 km or once a year, whichever comes first. The sump holds 0.70 litres, so budget for that volume of quality motorcycle-specific engine oil. Always use the correct viscosity grade as specified in the owner's manual.

Carburetor upkeep

Keep the carburetors clean and free of deposits. If the YZ125X has been stored, strip and clean the carb float bowls before attempting to start it. Pilot jets are the first to block and the last to be checked - always include them in any carb rebuild.

2021 Yamaha YZ125X - Frequently Asked Questions

What engine does the 2021 Yamaha YZ125X have?

The 2021 Yamaha YZ125X uses a Single cylinder, two-stroke engine with 125 cc of displacement.

How much does the 2021 Yamaha YZ125X weigh?

The 2021 Yamaha YZ125X weighs 94.8 kg. This is the manufacturer's wet figure.

What is the fuel tank capacity of the 2021 Yamaha YZ125X?

The 2021 Yamaha YZ125X has a 8-litre fuel tank.

Is the 2021 Yamaha YZ125X suitable for shorter riders?

The 2021 Yamaha YZ125X has a seat height of 975 mm. This is towards the tall end of the spectrum and will require most riders under 175 cm to tiptoe at stops.

What brakes does the 2021 Yamaha YZ125X have?

The 2021 Yamaha YZ125X uses Single disc. Hydraulic. at the front and Single disc. Hydraulic. at the rear.

What tyre sizes does the 2021 Yamaha YZ125X use?

The front tyre size on the 2021 Yamaha YZ125X is 90/90-21.

How much oil does the 2021 Yamaha YZ125X take?

The 2021 Yamaha YZ125X takes 0.70 litres of engine oil at a full oil and filter change. Always verify against the dipstick or sight glass after filling.

Yamaha YZ125X Spec Evolution

The Yamaha YZ125X was produced across 5 model years (2017-2023). The table below highlights the key specifications that changed across the production run - useful whether you are comparing years or tracking down a specific variant.

Specification	2017	2020	2021	2022	2023
Wet Weight	93.5 kg / 206.1 lbs	94.8 kg / 209.0 lbs	94.8 kg / 209.0 lbs	94.8 kg / 209.0 lbs	96.2 kg / 212.0 lbs
Seat Height	-	975 mm / 38.4 in.	975 mm / 38.4 in.	975 mm / 38.4 in.	970 mm / 38.2 in.
Fuel Capacity	8.00 litres / 2.11 gallons	8.00 litres / 2.11 US gallons	8.00 litres / 2.11 US gallons	8.00 litres / 2.11 US gallons	6.81 litres / 1.80 US gallons
Displacement (cc)	124.00 cc	125.0 cc	125.0 cc	125.0 cc	125.0 cc
Displacement (ci)	7.57 cubic inches	7.63 cubic inches	7.63 cubic inches	7.63 cubic inches	7.63 cubic inches
Oil Capacity (Quarts)	0.05 quarts	0.74 US quarts	0.74 US quarts	0.74 US quarts	0.74 US quarts
Frame Type	Semi-double cradle aluminium frame	Semi-double cradle aluminium frame	Semi-double cradle aluminium frame	Semi-double cradle aluminium frame	Semi-double cradle aluminium
Wheelbase	1,443 mm / 56.8 in.	1455 mm / 57.3 in.	1455 mm / 57.3 in.	1455 mm / 57.3 in.	1455 mm / 57.3 in.