If you have a 2 stroke dirt bike and you’re mixing fuel, then it’s both a frustration yet something you really need to get right.
Like one of those necessary evils, it’s certainly necessary if you’ve got a two banger and need to keep it in tip-top condition. While we know it needs to be done, a lot of dirt bike riders get confused and go searching online for the answers.
The best 2-stroke fuel ratio is the one recommended by your manufacturer, though 40:1 is considered to be standard for modern-day 2-strokes. KTM, Honda, Yamaha, Kawasaki and Suzuki have their fuel-to-oil ratios published online and in the user manuals. Failing this, your local dirt bike mechanic can provide some guidance and recommendations.
It’s generally safer and easier to simply call up your local dealership. Even if you didn’t buy the dirt bike from them, you’ll find them to be accommodating and able to provide a clear and concise answer.
2-Stroke Fuel Ratios
The premix ratios recommended by leading dirt bike manufacturers is one based on racing your dirt bike. At full capacity, your dirt bike obviously operates at such an intense pace as opposed to cruising around the ranch and doing jumps.
Therefore, we can say that the extra oil is just an overkill yet if you’ve got the funds, then go right ahead! Then again, manufacturers have the caruretor setup for this right mixture of petrol, oil and air. Changes of any notable ratio will require you to make some changes to the carby and jets to accommodate properly.
40:1 as we mentioned at the top of this article is ideal for the casual rider. Yet don’t get too worried if you’re putting too much oil in, as you won’t really damage it that much. You could cause some fouled plugs. This is mild compared to completely seizing your engine or prematurely wearing it out.
| Ratio | OZ per Gallon | Millilitres per Litre |
| 50:1 | 20 | 2.56 |
| 40:1 | 25 | 3.2 |
| 32:1 | 31 | 4 |
| 25:1 | 40 | 5.12 |
Again, individual bikes will have their ratios mentioned by their manufacturer. They can also vary year on year as the engines are upgraded or revised.
Professional Recommendations
You should consider that this task gets easier the more you do it. Yep – the first time that you mix oil and petrol, it feels a little weird. “Am I putting in too much or too little?” among other questions that might be running through your head. That’s why professional recommendations are a wise idea.
To mix 2-stroke dirt bike oil, follow these steps:
- Get yourself an oil measuring cup. There are several available but our #1 recommendation is this one on Amazon.
- Place the measuring cup on a flat and stable surface. Add in the required oil and fuel and mix together.
- Add the mixture into the fuel tank. Don’t start your dirt bike right away as you’ll want to allow some time for the oil to mix properly through your fuel tank.
- Properly rinse the measuring cup. If you leave it with residue oil/fuel mix, then, unfortunately, dust and other foreign particules can stick to the insides which can then leech into your fuel tank later on. Trust us – that causes real havoc!
The first time is the most concerning, but it gets easier and easier. Like popping that first wheelie, it just takes practice.
The 2-Stroke Oil Dangers
Now, some things that you definitely don’t want to be doing is buying cheap 2-stroke oil. This is a really bad idea and a quick pathway to the premature death of your engine. Get yourself premium oil. Yes – it costs more, but so does a rebuild!
Next – don’t go mixing different manufacturer oils together. Chances are that you’ll start clotting up your engine which isn’t what you really want mid-way through an epic run through the forest. Just use up your old oil then do a full drain before trying a new brand.
Finally – don’t forget the petrol! Don’t skimp on this and go for high octane gas/petrol like 95 or 98. 91 octane just isn’t enough for a performance-driven bike that’s designed to be revved hard and perform even harder.
Understanding the Basics
It’s hard to know sometimes how to read ratio charts properly. While we provided a chart above, what does this mean in plain and simple English? Well, it’s pretty simple.
50:1 means that for every 50 parts of petrol you have, you need to add 1 part of oil. You need to take into account the volume of your fuel tank.
Let’s say your 2 banger holds 10 litres. Well, you mix your fuel at say 50:1 then you have 200 millilitres of oil to add. Ratios are based on millilitres as opposed to gallons or ounces as it’s more tricky.
Finally – if you’re too worried, then get a buddy to help you out. There’s nothing shameful to ask for help to get the ratios done properly. What’s more shameful is a full engine rebuild!
