#1
★ Top Pick
Valvoline 4-Stroke Motorcycle Full Synthetic 10W-40 Motor Oil 1 Quart
The GN125's air-cooled 124cc single runs hot and tolerates minimal lubrication margin, so full synthetic 10W-40 is a smart match — it handles the thermal stress better than conventional oil and the viscosity sits right in Suzuki's recommended range for this engine. The 1-quart bottle covers a full oil change with a little left over for top-ups. Caveat: full synthetic is overkill cost-wise for a bike this basic; conventional 10W-40 does the job fine if budget matters.
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