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Yamaha YZ125

Maintenance specs for 1 variant of the Yamaha YZ125 — from 1985 to 2026.

19852026 Yamaha YZ125

125cc Liquid-Cooled 2-Stroke Single (YPVS) · Chain

37 hp / lb-ft

Engine Oil

WeightYamalube 2-R or Yamalube 2-S 2-stroke oil (premix 32:1)

Transmission

Type6-Speed
FluidSAE 10W-40 JASO MA
Drain & fill0.7 qt

Coolant

TypeEthylene glycol 50/50 mix
Capacity0.8 qt
Shop coolant

Brake Fluid

TypeDOT 4
Shop DOT 4

Fuel

Tank1.85 gal
TypePremium 91 (premixed with 2-stroke oil at 32:1)

Tires

Front80/100-21
Rear100/90-19
Pressure (front)14 PSI
Pressure (rear)14 PSI

Spark Plugs

Gap0.022 in
Shop spark plugs

Service Intervals

Oil change225 mi
Trans service450 mi
Coolant flush1,500 mi
Brake fluid1,500 mi
Spark plugs450 mi
Air filter150 mi