My MPG

[yamaha fj rider]

Last fill up I was about 140-150 miles on that tank but there was some time spent at 130-135 mph. Gas goes fast at a ton plus.

Kurt

[FJ111200]

I don't usually bother about MPG but on a recent run with friends i began to take a bit of interest, only a bit though.
Now then, we were both on XS1100's, and filled up from full, both after a 103 mile run.  My friend put in 11 litres and i put in 19  . So i got home and adjusted the carbs and went out for a run and measured the result which was to me an amazing 48 MPG. Result. There were some factors, but that is irrelevant.
So a couple of weeks later i'm out on my other XS and measured the MPG at 39 MPG. Not a great deal in it yes?
Now the only thing i can put it down to is the size of the rear wheels. One, the 48 MPG being a 17inch and the other, the 39 MPG, a 16inch.
OK, there are a few other contributing factors between the two bikes, but nothing major.
So the point i'm trying to make, could it be that the various MPG figures for the FJ's is the use of different size rear wheels and obviously the difference between the sprocket sizes.
I'm going out on my XJR1200 this weekend, never bothered to work out the MPG on that either, but i will this weekend, and that is running a 17inch rear wheel, stock FJ1200 3CV carbs and standard sprockets.

[FJmonkey]

Tire and wheel size does not make that much difference. The 16" wheel takes a taller tire. The diameter of a 150/80/16 is 25.45 inches. A 170/55/17 is 24.35 and 180/50/17 is 24.08. The larger wheel is getting slightly smaller. Check out www.gearingcommander.com where you can play with wheel/tire/sprocket combinations.

[ribbert]

I don't usually bother about MPG but on a recent run with friends i began to take a bit of interest, only a bit though.
Now then, we were both on XS1100's, and filled up from full, both after a 103 mile run.  My friend put in 11 litres and i put in 19  . So i got home and adjusted the carbs and went out for a run and measured the result which was to me an amazing 48 MPG. Result. There were some factors, but that is irrelevant.
So a couple of weeks later i'm out on my other XS and measured the MPG at 39 MPG. Not a great deal in it yes?
Now the only thing i can put it down to is the size of the rear wheels. One, the 48 MPG being a 17inch and the other, the 39 MPG, a 16inch.
OK, there are a few other contributing factors between the two bikes, but nothing major.
So the point i'm trying to make, could it be that the various MPG figures for the FJ's is the use of different size rear wheels and obviously the difference between the sprocket sizes.
I'm going out on my XJR1200 this weekend, never bothered to work out the MPG on that either, but i will this weekend, and that is running a 17inch rear wheel, stock FJ1200 3CV carbs and standard sprockets.

The OD between the wheels is neglegible. Certainly the gearing will make a difference but not by the sort of margin in your example.
My bike returned 52mpg ( Imp. gals )  for about a year, has dropped as low as 38 and for the last 12 mths has hovered around 46.  No gearing changes were made.
The FJ is a toy and within reason as long as it's running well and pulling hard I don't really care.
As someone here put it beautifully - "riding an FJ for economy is like going to a prostitute for a hug"

[FJ111200]

    OK, i won't bother then. 

[skiziks64]

I'm getting anywhere from 34-40 mpg with my 85 1100. and I ride double with my wife most of the time. I weigh 195 and she's like 135. Today was the worst mileage I've gotten so far with it and that was 34.

[Bob]

<...>
As someone here put it beautifully - "riding an FJ for economy is like going to a prostitute for a hug"

Great line...

I do keep track of my fuel consumption as a diagnostic tool. It was handy when I was working on the carbs.
FWIW: with the 18 / 49 sprocket mix I was averaging around 6.4 l/100km (36.2 mp(U.S.)g). Now, with 18 / 40 I'm seeing 5.7 l/100km (41.2 mpg).
When my carbs were in bad shape I was using 8 l/100km (29.4 mpg)

[FJ111200]

  OK, i won't bother then. 

Yeah well i did bother, and it's working out at 45 MPG  (UK).  I'm happy with that.

[fj11.5]

bad mpg is the price for having fun, I'm willing to pay the price