95 gasoline or 98 gasoline? Which is best for my motorcycle?

Through our Motoguia office, our friend Tori told us that he is about to get his new Honda Forza for the first time and has doubts about whether it is better to use 95 gasoline or 98 gasoline. There are many opinions on the matter and cross information, so Let's try to untangle the handle.

The first thing we must be clear about is what these numbers refer to, and these have to do with the octane rating of each type of gasoline. So, 95 gasoline has 95 octane and 98, well, 98… Up to that point we have it more or less easy. It is a percentage in which the octanes are actually called isooctane, and the rest up to 100 is covered by heptane. And this is the important detail. And yes, there are fuels that exceed the index 100.

Why do we say what is important? Well, because what this octane rating measures is the self-detonation capacity of the gasoline inside the cylinder. The lower the octane level, the easier it is for the gasoline to detonate due to pressure without causing the spark plug to spark. If this happens sooner or later we will have problems, because it will force the piston and connecting rod to not complete the cycle correctly, losing performance and potentially leading to mechanical failures and/or breakages.

But is 95 or 98 gasoline better?

In reality, the best gasoline is the one your motorcycle needs. That is, if your motorcycle engine is designed to work with 95 octane gasoline, you can fill the tank without fear. Now, if the engine is prepared for 98 octane and you put 95 gasoline in it, sooner or later you will have problems due to self-detonation.

Currently, even the sportiest motorcycles on the market in Spain are prepared to use 95 octane so, in reality, it is not necessary to fill the tank with 98, which is also usually much more expensive. Although if you do it you won't have any mechanical problems. So when in doubt

There are those who claim that with 98 octane gasoline, even if the engine is 95, you get more power and lower consumption. That is something that in my experience I have not been able to corroborate. And even if it is true, they are such minimal differences in percentage that they are negligible. Imagine gaining 1% or 2% performance on a 15 HP motorcycle. You would have 0.15 more HP and between 15 and 30 cents less for each liter you had refueled.

There is no tangible evidence that 98 octane gasoline has better performance in an engine prepared for 95

In reality, in terms of performance and fuel economy, the additives added to the gasoline may have more influence than the octane rating. But that is another issue that has nothing to do with it and about which, by the way, there is also a lot of controversy.

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