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2011 Yamaha YZ125 Overview
The 2011 Yamaha YZ125 is a cross / motocross motorcycle built around 124 cc of displacement. Under the tank sits a Single cylinder, two-stroke engine running Double Overhead Cams/Twin Cam (DOHC) valve actuation, a compression ratio of 8.6:1. The bore and stroke measures 54 x 54.5 mm. From a practical standpoint, the 2011 YZ125 tips the scales at 94.4 kg, carries a 7.95-litre fuel tank, offers a seat height of 998 mm and spans a 1,443 mm wheelbase. Scroll down for the complete 2011 Yamaha YZ125 spec sheet covering every technical detail from suspension travel to tyre sizes.
2011 YZ125 - Pros & Cons
Strengths
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Factory engineering: The 2011 Yamaha YZ125 represents Yamaha's engineering at the time, with a specification built around real-world usability.
Considerations
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🔧
Carburetor fuelling: Carbureted engines need occasional jetting attention and can be reluctant in cold weather or at altitude compared to modern fuel-injected alternatives.
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Tall seat height: The 998 mm seat height will challenge shorter riders - tiptoeing at low speeds is something to factor into your decision.
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Modest fuel capacity: The 7.95-litre tank means more frequent fuel stops on longer rides, which is worth planning around on touring routes.
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Chain final drive upkeep: Chain final drive needs regular cleaning, lubrication and tension checks to get full life out of the sprockets.
Wear Points & Servicing Notes
Carburetor maintenance
The YZ125 uses carburetion rather than fuel injection, which means jetting is altitude- and temperature-sensitive and benefits from a clean-and-rejet after extended storage or an exhaust change.
Valve clearance checks
Double Overhead Cams/Twin Cam (DOHC) valve actuation on the YZ125 means clearances should be checked at the manufacturer's specified interval - they can tighten as mileage accumulates, and a light top-end tick is usually the first sign.
Brake disc and pad wear
The Single disc. Wave front brake gives strong, progressive stopping power. Disc thickness and pad depth are worth checking at every tyre change, since worn pads can score the disc surface.
Suspension condition on used examples
Up front, the YZ125 runs Speed-sensitive system inverted fork and Fully adjustable single shock at the rear. On a used example, check fork seals for weeping oil and test the rear linkage for play - seals are a relatively cheap fix but useful when negotiating price.
Final drive maintenance
Final drive is by chain - expect to clean and lube it every few hundred kilometres and check tension regularly; a neglected chain wears the sprockets faster than the chain itself.
Frame & chassis check
The frame is Aluminium - worth a visual check for corrosion or impact damage around the head-stock and swingarm pivot on any used example, since frame damage is far costlier to fix than any service item.
Low-speed handling
At just 94.4 kg, the YZ125 is light enough to manhandle easily at a standstill - one of the practical advantages of its class.
YZ125 - Buying & Maintenance Guide
What to check before buying
When inspecting a used 2011 Yamaha YZ125, 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 YZ125 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 YZ125. 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 YZ125 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.
Valve clearance service
Check that valve clearances have been adjusted at the correct intervals on any used YZ125. A bike with clearances out of spec doesn't always feel obviously wrong - but tight clearances accelerate valve seat wear. Ask for service documentation proving it's been done.
2011 Yamaha YZ125 - Frequently Asked Questions
What engine does the 2011 Yamaha YZ125 have?
The 2011 Yamaha YZ125 uses a Single cylinder, two-stroke engine with 124 cc of displacement.
How much does the 2011 Yamaha YZ125 weigh?
The 2011 Yamaha YZ125 weighs 94.4 kg. This is the manufacturer's wet figure.
What is the fuel tank capacity of the 2011 Yamaha YZ125?
The 2011 Yamaha YZ125 has a 7.95-litre fuel tank. At around 5-6 litres per 100 km, that is roughly 132-159 km between stops.
Is the 2011 Yamaha YZ125 suitable for shorter riders?
The 2011 Yamaha YZ125 has a seat height of 998 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 2011 Yamaha YZ125 have?
The 2011 Yamaha YZ125 uses Single disc. Wave at the front and Single disc. Wave at the rear.
What tyre sizes does the 2011 Yamaha YZ125 use?
The 2011 Yamaha YZ125 runs 21/7-10 front and 100/90-M19 rear tyres. A good selection of sport, touring and all-weather rubber is available in these sizes.
How much oil does the 2011 Yamaha YZ125 take?
The 2011 Yamaha YZ125 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 YZ125 Spec Evolution
The Yamaha YZ125 was produced across 21 model years (2002-2023). 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 |
2002 |
2004 |
2005 |
2006 |
2007 |
2008 |
2009 |
2010 |
2011 |
2012 |
2013 |
2014 |
2015 |
2016 |
2017 |
2018 |
2019 |
2020 |
2021 |
2022 |
2023 |
| Wet Weight |
- |
- |
- |
- |
- |
- |
94.3 kg / 208.0 lbs |
94.3 kg / 208.0 lbs |
94.4 kg / 208.0 lbs |
94.4 kg / 208.0 lbs |
93.9 kg / 207.0 lbs |
93.9 kg / 207.0 lbs |
94.8 kg / 209.0 lbs |
94.8 kg / 209.0 lbs |
94.8 kg / 209.0 lbs |
93.9 kg / 207.0 lbs |
93.9 kg / 207.0 lbs |
93.9 kg / 207.0 lbs |
93.9 kg / 207.0 lbs |
94.8 kg / 209.0 lbs |
94.8 kg / 209.0 lbs |
| Dry Weight |
87.5 kg / 192.9 lbs |
87 kg / 191.8 lbs |
- |
86 kg / 189.6 lbs |
86.2 kg / 190.0 lbs |
86.2 kg / 190.0 lbs |
- |
- |
- |
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210.5 kg / 464.1 lbs |
59 kg / 130.1 lbs |
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- |
- |
- |
- |
- |
- |
- |
- |
| Engine Detail |
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- |
- |
- |
- |
- |
- |
- |
- |
Reed-valve inducted |
Reed-valve-inducted |
Reed-valve-inducted |
Reed-valve-inducted |
Reed-valve-inducted |
Reed-valve-inducted |
Reed-valve-inducted |
Reed-valve-inducted |
Reed-valve-inducted |
Reed-valve-inducted |
Reed-valve-inducted |
Reed-valve-inducted |
| Engine Type |
Single cylinder |
Single cylinder |
Single cylinder |
V2 |
Single cylinder |
Single cylinder |
Single cylinder |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
Single cylinder, two-stroke |
| Top Speed |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
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120.0 km/h / 74.6 mph |
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- |
- |
- |
96.0 km/h / 59.7 mph |
- |
- |
- |
- |
| Seat Height |
994 mm / 39.1 in. |
992 mm / 39.1 in. |
993 mm / 39.1 in. |
998 mm / 39.3 in. |
998 mm / 39.3 in. |
998 mm / 39.3 in. |
998 mm / 39.3 in. |
998 mm / 39.3 in. |
998 mm / 39.3 in. |
998 mm / 39.3 in. |
998 mm / 39.3 in. |
998 mm / 39.3 in. |
975 mm / 38.4 in. |
975 mm / 38.4 in. |
975 mm / 38.4 in. |
975 mm / 38.4 in. |
975 mm / 38.4 in. |
975 mm / 38.4 in. |
975 mm / 38.4 in. |
39 mm / 1.5 in. |
980 mm / 38.6 in. |
| Fuel Capacity |
- |
- |
7.94 litres / 2.10 gallons |
8.00 litres / 2.11 gallons |
7.94 litres / 2.10 gallons |
7.94 litres / 2.10 gallons |
7.94 litres / 2.10 gallons |
7.94 litres / 2.10 gallons |
7.95 litres / 2.10 gallons |
7.95 litres / 2.10 gallons |
7.95 litres / 2.10 gallons |
7.95 litres / 2.10 gallons |
7.95 litres / 2.10 gallons |
7.95 litres / 2.10 gallons |
8.00 litres / 2.11 gallons |
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 |
6.81 litres / 1.80 US gallons |
| Oil Capacity (Quarts) |
- |
- |
- |
- |
- |
- |
- |
- |
0.05 quarts |
- |
- |
- |
- |
- |
0.05 quarts |
0.05 quarts |
0.74 US quarts |
0.74 US quarts |
0.74 US quarts |
0.74 US quarts |
0.74 US quarts |
Key Specifications
Engine
Single cylinder, two-stroke
Power
Not published by manufacturer
Torque
Not published by manufacturer
Top Speed
Not published by manufacturer
Weight
94.4 kg / 208.0 lbs
Fuel Capacity
7.95 litres / 2.10 gallons
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Full 2011 Yamaha YZ125 Specifications
Colours
Team Yamaha Blue/White
Warranty
30 Day (Limited Factory Warranty)
Ground Clearance (mm)
386 mm
Ground Clearance (in.)
15.2 inches
Seat Height
998 mm / 39.3 in.
Wheelbase
1,443 mm / 56.8 in.
Height
1,316 mm / 51.8 in.
Length
2,136 mm / 84.1 in.
Width
828 mm / 32.6 in.
Oil Capacity (Quarts)
0.05 quarts
Oil Capacity (l)
0.70 litres
Fuel Capacity
7.95 litres / 2.10 gallons
Wet Weight
94.4 kg / 208.0 lbs
Fuel Control
Double Overhead Cams/Twin Cam (DOHC)
Engine Type
Single cylinder, two-stroke
Bore x Stroke (in,)
2.1 x 2.1 inches
Bore x Stroke (mm)
54.0 x 54.5 mm
Displacement (ci)
7.57 cubic inches
Displacement (cc)
124.00 cc
Fuel System
Carburettor. Mikuni TMX 38
Compression Ratio
8.6:1
Engine Lubrication
Dry sump
Ignition
CDI
Starter
Electric
Final Drive
Chain
Gearbox
6-speed
Primary Drive
2WD; Sealed O-Ring Chain, Eccentric Adjustment
Frame Type
Aluminium
Suspension - Front
Speed-sensitive system inverted fork
Suspension - Rear
Fully adjustable single shock
Wheel Travel - Front
300 mm / 11.8 in.
Wheel Travel - Rear
315 mm / 12.4 in.
Lighting system
Dual 30W Krypton multireflector Headlights and 3.9/0.5W LED Brake light
Brakes - Rear Diameter (in.)
9.6 inches
Brakes - Rear Diameter (mm)
245 mm
Brakes - Front Diameter (mm)
250 mm
Brakes - Front Diameter (in.)
9.8 inches
Brakes - Front
Single disc. Wave
Brakes - Rear
Single disc. Wave
Tyres - Front
21/7-10
Tyres - Front
80/100-M21
Tyres - Rear
100/90-M19
Specifications are compiled from manufacturer documentation and cross-referenced
technical sources, and corrected on an ongoing basis.
Spot an error? Let us know.
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