Fuel Economy Question

[cowboyup3371]

I think I know the answer to this already but I'm looking for verification.

If I'm running at 65 to 70 mph with a 25 to 35 mph crosswind/headwind daily (typically runs S to SE to E), my fuel economy will be a lot less than if I'm running in the mountains at 55 to 60 and very little wind if at all, correct?

I am averaging 43 to 47 mpg in the above conditions on a daily basis while if I'm in the mountains I'll get 50+. Does this mean I may still have a fuel delivery issue (maybe running too lean on my daily drives?) or would this be expected given the above conditions? The lean idea being that I don't have as much fuel getting to the engine thus making it work harder?

I ask this due to comments from some that my 550 should be able to hit 50+ all the time. But I think that is considering being in town doing less than 65mph and little wind since it's blocked by the buildings.

[kirkn]

You don't have any problem, based on those numbers, IMO.

Aerodynamic drag goes up by the CUBE of speed, or some such extreme non-linear relationship. And, the average standard bike + rider has aerodynamics of a barn door. So, 100 (apparent speed) is a WORLD of difference from 55...

Just my two cents.

Kirk

[cody3935]

im jealous i only get like 30-31pmg

[BassCliff]

Hi,

I think you're good. Depending on conditions, my bike has ranged between 31-45 mpg.


Thank you for your indulgence,

BassCliff

[wesmoon]

On my trip to road america last weekend 70mph for 3 hours I got 48 mpg on my 11e. But I'm geared slightly to tall lol 70 mph I'm clocking under 4k rpm

[7981GS]

On my trip to road america last weekend 70mph for 3 hours I got 48 mpg on my 11e. But I'm geared slightly to tall lol 70 mph I'm clocking under 4k rpm

On my bumped up compression, cams and carbs 1100 2-valve with a 2.56:1 final drive ratio,
I get 47.5 typically with no regard to the speed limits (revenue enhancing) signs.
At 4,100-4,200 it is showing 75 and at 4,500ish it is showing 85.

Cowboy, you stated that your mileage goes up in higher elevations.
That would indicate that perhaps you should drop one main jet size for your normal elevation.
Are you typically running above 3,500 feet?

Daniel

[cowboyup3371]

Daniel, my elevation at the house is 6300 feet. The mountain passes I'm riding at is 8500+.

[Steve]

I agree, your numbers look pretty good.

Just to show how speed affects mileage, several years ago, we were on our way to our annual GoldWing trip to West Virginia. We were hurrying a bit to get to a particular eating place in time to catch the lunch special. We were doing about 75 mph on the freeway, into a 15-20 mph headwind. She usually hits reserve on her tank at about 140 miles. That day, it happened at 90 miles. Mileage was about 28-29 mpg for two consecutive tanks. After lunch, we hit some 2-lane roads and slowed down a bit, mileage went up to the upper 30s. A few days later, on the way home, we were still in the mountains (2-3,000 feet elevation). Speed was in the 50-60 mph range, but, for several consecutive tankfuls, mileage was over 50, topping out at 58.9 mpg.

Road speed is a major factor. Add in a headwind, it's even worse.
Elevation can make a difference, but you are not changing all that much.

.

[7981GS]

Cowboy, drop one main jet size please.
I am at 5,000 feet and my '81 850 is absolutely happy with one jet size up running pods and stock exhaust. (117.5's)
Not the 5-10 larger that most on here would recommend. It would simply not run with those recommendations at this altitude.


Daniel