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Master your MT: Get the Ultimate VVA Service Manual & Bible now!
Torque Spec, Fluid Capacity, and Repair Guide—Optimized for Your Mobile Screen.
Master Your MT-125: The Ultimate Owner’s Technical Bible
Master Your MT-125: The Ultimate Owner’s Technical Bible
Stop guessing and start wrenching. Get the definitive, step-by-step guide to maintaining, troubleshooting, and perfecting your Yamaha MT-125—all in one place.
Common Fault Decoders: Learn to diagnose the infamous "Yamaha Tick" and VVA glitches before setting foot in a garage.
Technical Specs: No more hunting through forums; get every torque setting and fluid capacity instantly.
Repair Guides: Clear, high-quality advice that makes complex engine and electrical work simple.
Performance Optimisation: Proven tips to keep your 125cc engine running at its absolute peak.
The Survival Archive: A comprehensive library designed for riders who demand reliability and precision.
Track-Ready Precision: optimised gearing setups, fluid formulas, and chassis care secrets to keep your machine crisp under heavy redline abuse.
Frequently Asked Questions
Frequently Asked Questions
Which bike models does this Bible cover?
Which bike models does this Bible cover?
This technical guide is specifically designed for the Yamaha MT-125 and MT-15 (MT-150) platforms. It covers all major generations, including the earlier models and the newer VVA (Variable Valve Actuation) engine versions.
Is this an official Yamaha service manual?
Is this an official Yamaha service manual?
No. This is an independent Technical Bible created for owners. While official manuals can be dense and hard to navigate, this guide is streamlined to focus on the most common repairs, maintenance tasks, and technical specs that owners actually need in the garage.
What kind of technical data is included?
What kind of technical data is included?
You get instant access to:
Torque Settings: Every critical bolt from the axles to the cylinder head.
Fluid Capacities: Exact measurements for oil, coolant, and fork fluid.
Maintenance Schedules: Know exactly when to check your valves or change your chain.
Real world owners: incites on common issues and fault from owners.
Can I access the guide on my phone?
Can I access the guide on my phone?
Yes. The Bible is fully optimized for mobile devices. It’s designed to be used as a digital companion while you are working on your bike, with large text and clear diagrams that are easy to read on a small screen.
How do I receive the guide after purchase?
How do I receive the guide after purchase?
Immediately after your payment is confirmed, you will receive a secure link to access the full Technical Library. You can bookmark this link for lifetime access across all your devices.
Do I need professional tools to use this guide?
Do I need professional tools to use this guide?
While we recommend basic quality tools (sockets, torque wrench, etc.), the guide is written for both beginners and experienced home mechanics. We break down complex tasks into manageable, step-by-step instructions.
MT-125 & MT-15 Engine & Performance Specs
MT-125 & MT-15 Engine & Performance Specs
Engine & Performance Specs
Engine & Performance Specs
Engine Type: 124.7cc / 155cc, Liquid-cooled, 4-stroke, SOHC, 4-valve (VVA equipped on 2019+ models).
Bore x Stroke: * 125cc: 52.0 mm x 58.6 mm
155cc: 58.0 mm x 58.7 mm
Compression Ratio: 11.2:1 (125cc) / 11.6:1 (155cc).
Maximum Power: * 125cc: 11.0 kW (15.0 PS) @ 9,000 rpm.
155cc: 13.7 kW (18.6 PS) @ 10,000 rpm.
Fuel System: Electronic Fuel Injection (EFI).
Fluids & Capacities
Fluids & Capacities
Engine Oil (Change only): 0.95 Litres.
Engine Oil (With filter removal): 1.00 Litre.
Recommended Oil Grade: SAE 10W-40 (API service SG type or higher, JASO standard MA).
Coolant Capacity: 0.48 Litres (Radiator + Engine).
Fuel Tank Capacity: 10 Litres (including reserve).
Fork Oil (per leg): 225cc - 230cc (Check specific year for level height).
Critical Torque Settings
Critical Torque Settings
Engine Oil Drain Bolt: 20 Nm (14 lb-ft).
Oil Filter Cover Bolts: 10 Nm (7.2 lb-ft).
Rear Axle Nut: 90 Nm (65 lb-ft).
Front Axle Bolt: 60 Nm (43 lb-ft).
Spark Plug: 13 Nm (9.4 lb-ft).
Front Brake Caliper Bolts: 35 Nm (25 lb-ft).
Chassis & Electrical
Chassis & Electrical
Tire Pressure (Front): 29 psi (2.00 bar).
Tire Pressure (Rear): 33 psi (2.25 bar).
Drive Chain Slack: 25.0–35.0 mm.
Spark Plug Type: NGK / CPR8EA-9 or CPR9EA-9.
Battery Type: 12V, 3.0 Ah (ETZ4V / YZ4V).
"Trying to flip through a massive 400-page factory PDF on a phone while your hands are covered in engine oil is impossible. This bible is completely optimized for a mobile screen. The large text layouts, clear component pictures, and quick-reference fluid specs made doing my periodic oil and filter change a breeze."
— Harry V., Bristol
"My MT-125 speedo clocks started flickering and condensing after a heavy storm, and a replacement unit from Yamaha is a joke. The speedo protection tips and electrical seal routines in this guide helped me strip, dry, and secure the casing properly before the circuit board fried completely. Saved me hundreds."
— Callum B., Coventry
"I was paranoid about stripping the aluminum engine casing threads while changing my oil filter and spark plug. Having every single exact torque setting—like the 10 Nm for the filter cover and 13 Nm for the plug—laid out in a clean chart gave me total confidence. Excellent guide for anyone maintaining a VVA generation MT."
— Nathan D., Leeds
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