If you’re running a SmartCarb-equipped dirt bike, ATV, or motorcycle, you already know the benefits—automatic altitude compensation, better throttle response, and improved fuel efficiency. But did you know that the type of fuel you use changes with the season?
That’s right—gasoline isn’t the same year-round. Refineries adjust the fuel blend depending on the time of year, and if you’re not paying attention, it could impact performance, starting, and fuel economy.
Why Does Fuel Change by Season?
The biggest difference between summer and winter fuel comes down to something called Reid Vapor Pressure (RVP). This measures how easily fuel evaporates.
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Winter fuel (high RVP) contains more volatile components (like butane) to help with cold starts.
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Summer fuel (low RVP) is refined to prevent excessive evaporation and vapor lock in hot temperatures.
If you run the wrong seasonal fuel, you could experience:
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Hard starts in the cold (low-RVP summer fuel in winter).
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Poor fuel atomization (high-RVP winter fuel in warm weather).
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Reduced throttle response & power due to improper vaporization.
How a SmartCarb Helps
A SmartCarb automatically compensates for air density changes, adjusting the air-fuel ratio dynamically. This means fewer adjustments compared to a traditional carburetor.
However, fuel volatility still plays a role. Even with a SmartCarb, using the correct seasonal fuel ensures optimal performance. Here’s how:
Winter Fuel + SmartCarb
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Better cold starts due to higher volatility.
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Can run slightly richer in warm weather.
- Best used in cold months to prevent hard starting.
Summer Fuel + SmartCarb
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More stable in heat (prevents vapor lock).
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Better fuel efficiency due to higher energy content.
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Harder to ignite in cold temps (longer cold starts).
- Best for hot months to maintain consistent throttle response.
Tips for Using the Right Fuel
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Check your local gas stations – Many switch blends in mid-September (to winter) and mid-April (to summer).
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If temperatures fluctuate, use up your old fuel before switching blends.
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Store fuel properly – Winter gas evaporates faster, so don’t leave it sitting too long.
Conclusion
Your SmartCarb does a lot of the work for you, but fuel selection still matters. Using the correct seasonal gas ensures easier starts, better power delivery, and maximum efficiency.
Dirt bikes are not designed to store gas—they are designed to burn it! Letting fuel sit too long can lead to evaporation, gum buildup, and reduced performance. The best way to ensure you always have the right fuel for the season? Ride year-round! Not only will you keep fresh fuel in your bike, but you'll also stay sharp on the trails, keeping the fun going no matter the weather.
So, get out there, burn that gas, and enjoy the ride!
