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The Complete Resource for Maintenance, Restoration, and Technical Specifications (2005–2017)
Comprehensive Technical Data for Carbureted and Fuel Injected (Fi) Models
Comprehensive Technical Data for Carbureted and Fuel Injected (Fi) Models
Whether you are restoring a classic 2005 Carburetor YBR or maintaining a late-model 2017 Fuel Injected (Fi) commuter, precision data is the difference between a reliable ride and a breakdown. This technical archive is the ultimate "survival bible" for the Yamaha YBR 125 (ED, Custom, and Factor), providing the exact specifications required for professional-grade maintenance.
The Ultimate Commuter, Decoded.
Whether you’re a first-time rider on a 2005 carburetor model or a seasoned commuter keeping a fuel-injected 2016 unit alive, the YBR 125 is the backbone of the road. But even the world’s most reliable workhorse needs the right care.
The YBR 125 Bible is a centralized technical hub designed to take you beyond the basic owner’s manual. We bridge the gap between "it won't start" and a perfect ride with:
Deep-Dive Specs: Detailed data for every generation (2005–2017).
Common Fixes: Solving the "missing" high-RPM issues and transmission wear.
Restoration Guides: From frame-up refreshes to simple bolt-on upgrades.
Don’t just ride it—master it.
FAQ Section (Drop-Downs)
FAQ Section (Drop-Downs)
What are the main differences between the Carb and EFI models?
What are the main differences between the Carb and EFI models?
The YBR 125 used a Mikuni carburetor from 2005 to 2006. From 2007 onwards (Euro 3 compliance), Yamaha switched to Electronic Fuel Injection (EFI). EFI models are more fuel-efficient and reliable in cold starts, while Carb models are easier for home mechanics to tune without diagnostic tools.
Why does my YBR 125 stutter at high RPMs?
Why does my YBR 125 stutter at high RPMs?
This is a common "ghost" issue often caused by a restricted fuel filter (on EFI models) or a failing ignition coil. Checking the spark plug gap (0.6–0.7mm) and cleaning the air filter usually resolves 80% of top-end bogging issues.
What is the best oil for a Yamaha YBR 125?
What is the best oil for a Yamaha YBR 125?
Use a high-quality 10W-40 4-stroke motorcycle oil (JASO MA or MA2 spec). Because the YBR has a wet clutch, avoid "Energy Conserving" car oils, as they can cause clutch slippage.
Tech Specs Section
Tech Specs Section
Engine & Transmission Data
Engine & Transmission Data
Engine Type: 124cc, Air-cooled, 4-stroke, SOHC, 2-valve.
Bore x Stroke: 54.0 mm x 54.0 mm.
Compression Ratio: 10.0 : 1.
Max Power: 7.5 kW (10.1 PS) @ 7,800 rpm.
Transmission: 5-speed, Constant Mesh.
Chassis & Dimensions
Chassis & Dimensions
Front Tyre: 2.75-18 42P.
Rear Tyre: 90/90-18 57P.
Front Brake: Single Disc, Ø 245 mm.
Rear Brake: Drum, Ø 130 mm.
Wet Weight: 124 kg (including full oil and fuel tank).
Service & Capacity Limits
Service & Capacity Limits
Engine Oil Capacity: 1.0 Litre (Total); 0.95 Litre (Periodic change).
Fuel Tank Capacity: 13 Litres (including approx. 3.4L reserve).
Valve Clearance (Cold): Intake 0.08–0.12mm / Exhaust 0.10–0.14mm.
Idling Speed: 1,300–1,500 rpm.
"I bought an old 2006 carbureted YBR that had been sitting in a shed for two years and wouldn't start. The restoration guides and precise fuel system specs in this bible helped me strip, clean, and reset the Mikuni carb to factory settings. She fired right up on the first press of the button."
— Greg M., Leeds
"I do delivery work on my 2014 fuel-injected YBR 6 days a week. I can't afford to have my bike stuck in a garage for days. This guide has paid for itself twenty times over. The service limits and valve clearance (tappet) data are so easy to follow that I do all my periodic maintenance on Sunday afternoons."
— Harvey J., London
"I bought an old 2006 carbureted YBR that had been sitting in a shed for two years and wouldn't start. The restoration guides and precise fuel system specs in this bible helped me strip, clean, and reset the Mikuni carb to factory settings. She fired right up on the first press of the button."
— Greg M., Leeds
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