TERRIBLE gas mileage - this one's different. promise.
 

My cbr has always got about 90-100 miles till the reserve. that's about 33mpg. I am pretty hard on it with accelerating. It just makes me happy. haha anyway, Thats pretty bad, but leagues better than my truck. Well, yesterday I filled up. Set the trip meter, and the light came on at 51 MILES?!?! that's absolute garbage... I would have thought FPR, but the bike shows no other symptoms.. Any ideas?

The light came on, but is it really that low?

Run another tank through it. Make sure to get it full, run it, and fill it again. See what you got then.

How much gas did 51 miles take to refill? If you only used a gallon then you know its not a gas mileage problem.

3.5 gallons, but to be fair, I only put 5 dollars in when the light came on the first time. Which was about 2 gallons

Always fill up to the tippy top before trying to monitor mileage.

Forgive if this doesn't apply, that Ethanol garbage in the gas really does a number on gas mileage. Make sure you put in the 87 octane. Not all stations have the 87 in the same position at the pump unit.

But even putting premium in is not going to affect it that much.

Now that the tank is full, you need to monitor this.

If you let your bike warm up properly before you go, how far you ride makes a difference too. For example, my commute in college was 3 miles each way. So, if I didn't have a real ride during that time, I was only getting about 90 miles to the tank. But when I'd take long spirited rides, I'd be back to 120 or so before the light came on. That's a substantial difference, and it was due to how much time the bike was running and heating up without the odometer ticking.

Now that you know the tank is full, lets see what happens. And you're sure the bike is running normally and that there isn't a fuel leak?

Filled up as much as possible.. light came on at 110 miles, however, that was a lot of 80mph interstate riding and some spirited acceleration.. I'm assuming the low mileage was due to the short commute around town.

110 is definitely back into the normal range. Glad you have some peace of mind now.

I feel so bad for you guys. The only time I've ever had my light come on at 110miles is when I ride to a canyon and use it as a track running lap after lap. I wonder why the massive difference in gas mileage. Anyone ever do compression or leak down tests on their motors?

My compression should be fine... Unless sitting up hurt it. It only has 2500 miles..