The gas gauge on the 500 is just below the speedometer, some people call it a "tripmeter" and it works perfectly as long as there's nothing wrong with the nut connecting the seat to the handlebars.
When mine gets to 240 and I still haven't put the petcock on RES, I start looking for a gas station. YMMV.
-CCinC

 

mine only goes to like 180 before Im switching to reserve, I thought you were a fairly aggressive rider Chris?

 

lol.. at 120 im looking for a gas station

 

I got to about 225 last tank(2005 Ninja 500R)without switching to reserve, but I'm fairly easy on her, given her delicate nature(actually she'll take beating without complaining). Seriously, I've only ridden about 6,000 miles so far but I've had no problems getting 200 to 225+ miles out of a tank without switching to reserve. I usually fill her up after 200 miles or so to be on the safe side but I like to get as much fresh gas in her as possible and not leave a lot of old gas in the tank.

 

my biggest mistake was sticking the gas pump spout ALL the way down and then just waiting till it "clicked" full. my dealer said he put "almost a full tank of gas" in it, and so i wasn't suprised when after 100 miles, it only took 1.5 gallons of gas.

i guess this would be lesson number one, never trust your dealer!

 

There's a difference between an aggressive rider and a fast one, Jamie. Any dipstick can rev the p33-p33 out of his bike from stoplight-to-stoplight. And anyway the 500 is my Dr.-Jekyll bike, my ZX9R is my Mr,-Hyde:

Peace!
-CCinC