I get around 45 mpg (10 miles/litre) from my 748 in daily use; maybe 50 mpg on a long run. Have got 174 miles from a tankful ni the past, nursing it a bit for the last few miles!
So about the same as edwyun above. Although those gallons are smaller in the States, aren't they?
The 750SSie that I had before was slightly better, nearly 50 mpg in ordinary use.
Also, I run stock cans. I suspect that makes quite a difference.
[Edited on 20-3-2006 by moto748]