Any one else notice gas mileage has decreased significantly?

[Diablo1]

I disagree with you and feel I am not off base.

Maybe it’s a gas problem specific to Phoenix? I haven’t seen any mileage change with my FJR in Chicago, NW Indiana or Michigan. Perhaps you need to take a long trip and get some gas from a different state to test the theory. Also make sure your brakes aren’t dragging.

 

[JQL]

Using Ethanol in your fuel will result in reduced miles per gallon (mpg) as the "energy" value of ethanol is less than that of petrol. Ergo, the more ethanol in the fuel, the fewer miles per gallon. Depending on your vehicle and driving style, it could be more costly, mpg-wise, to use the "cheaper" fuels blended with ethanol.

As to the use of ethanol. Nearly all motorcycles, and a large percentage of other vehicles, will sustain some form of damage, usually to fuel systems, when using more than a 10% ethanol mix. If you have a veteran or vintage vehicle, unless it's been converted (highly unlikely), any ethanol in the fuel will cause damage to the fuel system.

My 2019 FJR is rated for E10 according to the manual, but I will rarely use a fuel blend of more than 5% ethanol as it actually costs me more per mile (your mileage may vary so check for yourself). I would never, ever, use a fuel blend of more than 10% ethanol and will only use E10 when E5 or "E0" is not available.

For balance. My "commuter" motorcycle, not a Yamaha, is 12 years old. I bought her new and have covered 121,200 miles (~195,000 km). I have only ever used supermarket E5 in her and I have had no problems so far (famous last words) with the fuel system.

Although it is easy to remove ethanol from fuel, I wouldn't recommend it as, apart from the obvious dangers (fire etc.), there are some other caveats (octane rating being one).

 

[Azor50Ron]

Maybe it’s a gas problem specific to Phoenix? I haven’t seen any mileage change with my FJR in Chicago, NW Indiana or Michigan. Perhaps you need to take a long trip and get some gas from a different state to test the theory. Also make sure your brakes aren’t dragging.

How many miles and how often to you ride it? My mileage drops ~20% when it sits a couple of weeks.

 

[Old Guy]

I'm late to the game, but I record the odometer and fuel at each stop and keep tabs. If 89 octane is available at the pump I use it because Ivan suggests it with the ECU flash. Otherwise, it gets 87 octane. My mileage varies with riding style, wind conditions, etc. just like everyone else's. But I can't tell that it's gotten any worse. in the last several months.

 

[Diablo1]

How many miles and how often to you ride it? My mileage drops ~20% when it sits a couple of weeks.

Typically, I ride a few days per week. Most of my rides are 150-250 miles. I always reset the odometer at fill up and calculate actual mpg for the tankful, typically 43 mpg. A lot of stops and restarts will lower mileage because a cold engine uses more fuel. I’ve never noticed a decrease in my mileage from letting the bike sit a few weeks. I don’t know why that would happen.

 

[Azor50Ron]

Typically, I ride a few days per week. Most of my rides are 150-250 miles. I always reset the odometer at fill up and calculate actual mpg for the tankful, typically 43 mpg. A lot of stops and restarts will lower mileage because a cold engine uses more fuel. I’ve never noticed a decrease in my mileage from letting the bike sit a few weeks. I don’t know why that would happen.

Me either...old vehicles weren't sealed so evaporation...maybe mine's not airtight?
Have the same issue with my Vstar1300
I run premium fuel and get 38-40+mpg mostly small city (aka <50mph) driving these days.