Too little oil seizes the engine. Too much fouls the plug and smokes. Premix bikes only — Honda NC50 / PA50II use oil injection (see Honda guide).
Premix calculator
Set your target ratio, then enter how much gas or oil you have — the calculator solves for the other side. The fuel can shifts color as the ratio gets richer (more oil) or leaner.
Oil mix ratio chart
Quick reference for common premix ratios. US gallon = 128 fl oz.
| Ratio | Oil per US gallon | Oil per liter | Oil % by volume |
|---|
By Platform
| Engine | Typical stock | Notes |
|---|---|---|
| Puch E50 / ZA50 | 50:1 | Richer for break-in or 70cc kits (32:1–40:1). See Puch guide. |
| Tomos A35 / A55 | 50:1 | Quality synthetic; richer if kitted. Chain drive — see Tomos guide. |
| Peugeot 103 | 50:1 | European tuners often run 40:1 on performance builds. |
| Motobécane AV7 | 50:1 | Stock exhaust is restrictive; tune oil with jetting changes. |
| Minarelli V1 bikes | 50:1 | General, Cimatti, etc. — same premix rules. |
| Honda NC50 / PA50II | N/A premix | Oil injection tank — do not premix fuel unless pump removed. |
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