Model Maintenance Schedule
Yamaha YZ125 Maintenance Schedule
The Yamaha YZ125 is Yamaha's 125cc 2-stroke motocross bike. This page lists the maintenance intervals from the 2026 YZ125 owner's service manual, with race counts converted to the hours Yamaha prints beside them.
Key Intervals At A Glance
- Oil: Transmission oil: Change, every fifth race (about 12.5 hours).
- Air filter: Air filter element: Clean, every race (about 2.5 hours).
- Top end: Piston: Replace, every fifth race (about 12.5 hours).
- Fork: Front fork oil: Replace, every fifth race (about 12.5 hours).
How The Yamaha Schedule Works
Yamaha's YZ owner's service manuals use a maintenance interval chart with columns for after break-in, every race (about 2.5 hours), every third race (about 7.5 hours), every fifth race (about 12.5 hours) and as required. A few items, like coolant and brake fluid, are on calendar intervals instead.
If you count hours instead of races, Yamaha prints about 2.5, 7.5 and 12.5 hours of running beside the columns. This schedule is written for a motocross race bike that gets raced. Yamaha publishes these manuals for free in its official owner's manual library.
Yamaha YZ125 Service Intervals By Hours
The table below lists the core service items from the maintenance schedule in the 2026 YZ125 Owner's Service Manual (publication D68-2819U-51, English). Task wording follows the manual. Where the manual gives both an hour and a calendar interval, do the work at whichever comes first.
| Service task | Interval | First service |
|---|---|---|
| Piston: Check carbon/cracks, clean | Every race (about 2.5 hours) | After break-in |
| Piston: Replace | Every fifth race (about 12.5 hours) | None listed |
| Piston rings: Check end gap/damage | Every race (about 2.5 hours) | After break-in |
| Piston rings: Replace | Every third race (about 7.5 hours) | None listed |
| Piston pin and small end bearing: Check | Every race (about 2.5 hours) | None listed |
| Cylinder head: Check carbon, clean; check gasket, tighten nuts | Every race (about 2.5 hours) | After break-in |
| Cylinder: Check score marks/wear, clean | Every race (about 2.5 hours) | After break-in |
| Power valve (YPVS): Check carbon/cracks; clean | Every race (about 2.5 hours) | After break-in |
| Clutch: Check housing/plates/springs, adjust | Every race (about 2.5 hours) | After break-in |
| Transmission oil: Change | Every fifth race (about 12.5 hours) | After break-in |
| Transmission: Check for damage / replace bearings | As required | None listed |
| Shift forks, guide bars, shift drum: Check/replace | As required | None listed |
| Rotor nut (flywheel magneto): Tighten | Every fifth race (about 12.5 hours) | After break-in |
| Kickstarter system: Check idle gear | As required | None listed |
| Exhaust system: Check pipe/muffler carbon | Every race (about 2.5 hours) | After break-in |
| Crankshaft: Check carbon/damage; clean | Every fifth race (about 12.5 hours) | None listed |
| Carburetor: Check settings, adjust and clean | Every race (about 2.5 hours) | After break-in |
| Spark plug: Check condition, clean and regap | Every race (about 2.5 hours) | After break-in |
| Drive chain: Check slack/alignment, lubricate | Every race (about 2.5 hours) | After break-in |
| Cooling system: Check coolant level/leakage, hoses | Every race (about 2.5 hours) | After break-in |
| Coolant: Change | Every 2 years | None listed |
| Air filter element: Clean | Every race (about 2.5 hours) | After break-in |
| Fuel line: Clean and check for leakage | Every third race (about 7.5 hours) | After break-in |
| Brakes: Adjust/lubricate/check/tighten | Every race (about 2.5 hours) | After break-in |
| Brake pads: Replace | As required | None listed |
| Brake fluid: Replace | Every year | None listed |
| Front fork: Check operation/leaks, clean and lubricate dust seal | Every race (about 2.5 hours) | After break-in |
| Front fork oil: Replace | Every fifth race (about 12.5 hours) | After break-in |
| Front fork oil seals / protector seal: Replace | As required | None listed |
| Shock absorber assembly: Check operation and adjust | Every race (about 2.5 hours) | After break-in |
| Shock absorber assembly: Lubricate with lithium-soap-based grease | Every third race (about 7.5 hours) | None listed |
| Drive chain roller and support guide: Check/replace | As required | None listed |
| Rear suspension (linkage): Check/tighten; lubricate with moly grease | Every race (about 2.5 hours) | After break-in |
| Swingarm pivot bearings: Check looseness; lubricate | Every race (about 2.5 hours) | After break-in |
| Steering head: Check operation/free play | Every race (about 2.5 hours) | After break-in |
| Steering head bearings: Clean and lubricate | Every fifth race (about 12.5 hours) | None listed |
| Tires and wheels: Check pressure/run-out/spokes; tighten sprocket bolts | Every race (about 2.5 hours) | After break-in |
| Wheel bearings: Check looseness; lubricate | Every third race (about 7.5 hours) | None listed |
| Moving parts and cables: Lubricate | Every race (about 2.5 hours) | After break-in |
| Chassis fasteners: Check/tighten | Every race (about 2.5 hours) | After break-in |
The manual is the authority. Check the edition for your exact model year before ordering parts, and shorten intervals for mud, sand, heat or heavy loads.
Fluids And Capacities
| Item | Specification |
|---|---|
| Premix (engine oil) | YAMALUBE 2R, premix ratio 30 (break-in mixture: ratio 15) |
| Transmission oil type | Motor oil SAE 10W-40 type SG or higher |
| Transmission oil quantity | 0.70 L (0.74 US qt, 0.62 Imp.qt) |
| Transmission oil quantity (disassembled) | 0.76 L (0.80 US qt, 0.67 Imp.qt) |
| Coolant, radiator (including all routes) | 0.93 L (0.98 US qt, 0.82 Imp.qt) |
Ownership Notes
Yamaha's chart replaces the piston rings every third race (about 7.5 hours) and the piston every fifth race (about 12.5 hours), with the piston, rings, cylinder, head and YPVS power valve checked and cleaned every race. Transmission oil is changed after break-in and then every fifth race.
The manual specifies Yamalube 2R premix at a ratio of 30 to 1, with a richer 15 to 1 break-in mixture. See our YZ125 setup guide for chassis baseline tips.
Track The Yamaha YZ125 Schedule Automatically
MotoMind tracks these intervals automatically by engine hours. Add your Yamaha YZ125 to the garage, set each task to the interval in the table above, and update hours from your hour meter or the GPS ride tracker. Every task then shows as upcoming, due now or overdue, and your completed service builds a history you can export as a PDF when you sell the bike.
Other Yamaha Schedules
Compare with Yamaha YZ250F, Yamaha YZ450F, Yamaha YZ250, or browse every model in the maintenance schedules hub.
FAQ
How often should I change the gear oil on a Yamaha YZ125?
The 2026 Yamaha owner's manual lists transmission oil (Change) on this interval: every fifth race (about 12.5 hours). Ride in mud, sand or heat, or race hard, and shorten the interval.
When does a Yamaha YZ125 need a new piston?
The 2026 Yamaha owner's manual lists piston (Replace) on this interval: every fifth race (about 12.5 hours). Track engine hours closely so the top end is replaced on schedule rather than after a failure.
How often should I clean the air filter on a Yamaha YZ125?
The 2026 Yamaha owner's manual lists air filter element (Clean) on this interval: every race (about 2.5 hours). In dusty or sandy conditions, inspect it after every ride.
How often does the Yamaha YZ125 suspension need service?
The 2026 Yamaha owner's manual lists front fork oil (Replace) on this interval: every fifth race (about 12.5 hours).
Can an app track the Yamaha YZ125 maintenance schedule for me?
Yes. MotoMind tracks these intervals automatically by engine hours. Enter your Yamaha YZ125's hours or log rides with the GPS ride tracker, set the intervals from this table, and MotoMind shows what is upcoming, due or overdue.
Track The Yamaha YZ125 By Engine Hours
MotoMind tracks these intervals automatically by engine hours, so your Yamaha YZ125 gets oil, filters, top end and suspension service on time.
