It can easily vary this much. At 80 mph 10 or 15 mile head or tail wind can make a big difference. I am also amazed how fast people drive these bikes. Harley says the maximum speed on these bikes is 80 with 2up and 90 solo. Slow it down and you will get a lot better fuel mileage. I usually average about 60 and fill up ever 100 on the trip. Usually takes touch over two gallons

 

I never get anywhere near that type of mileage. My low fuel light comes on at 112-115 miles regularly and I put in 3.5 gallons. That's a little over 32mpg. I don't ride real hard and it's mixed driving. So should I be concerned?

Sorry, didn't mean to steal this thread.....

 

winter fuel.

 

Speedometer accuracy is not the issue because if the speedo is off, under or over it will be off consistantly.

So mileage and speed readings will not vary from tank to tank.

I have never noticed a change from winter to summer fuel mileage. Besides I believe most fuels are now 10% all year.

The only variable is that he changed his shift points.

The way he changed his shift points will drop his mileage. There should be no surprise for him.

The only thing is that I hope he has not based his mileage change on one tank full.

Back in the day I had a Chey 283 that would get 22 mpg. One tank full I got 25. I always topped off the tank the same. Why I got 25? Who knows, who cares? The thing is if I based my mileage claim on that one tank full I would not be stating the normal mileage.

Owners manual says fifth gear at 55.

 

Quote:

I have never noticed a change from winter to summer fuel mileage. Besides I believe most fuels are now 10% all year.

Do some research.

 

Yup, it's Winter fuel. Combined with cold temps, mileage drops considerably. Don't confuse Winter fuel with 10% ethanol blend, they are not the same. Winter fuel may or may not contain ethanol. Now, with that said, if your state or gas station has recently adopted ethanol, that also could be contributing to your mileage drop. Ethanol or Winter fuel, most likely Winter fuel or worse yet, both.

 

I based my mileage drop over 6 tanks of gas. i didnt change my shift points. The bike was running fine before when I shifted at 55 but now when i shift at 55 the engine is lugging and runs fine when i shift around 60 or 65. i guess i did change my shift points but for a reason.
Lou

 

You must be the tornado out there that Dorothy was talking about ...

 

I cleaned my stock Air filter,,threw It In the dishwasher,,
when the OL was at work.
Got a bump In mileage XD

 

True that, plus the colder the ambient temp, the more fuel is burned.