I get between 23-24 miles after switching to reserve. Then again, I avoid that. I know that a tank is a max 148 miles for me. I fill around 120 miles. My low fuel light comes on about 10 or 15 miles before reserve.
Unfortunately for you, these bikes can have a wide range of fuel consumption based on their set up. My bike has was running 35mpg on one carb
set up and then is running about 31 with the current set up (higher performance in the mid range) Also riding habits change it greatly. I can get the 35mpg with this set up, or I can ride like I stole it and drop it to 27mpg in a hurry.
In other words, your mileage may vary ...