Here is one of those easy 20-minute jobs that cost $0 and can save your butt on the trail. The job at hand is calibrating your fuel gauge. If you ride in areas where fuel stops are sparse, knowing exactly how much gas you have in the tank is fundamental in estimating how far you can travel before you need to stop. To complete the job you will need a piece of siphon hose, some bright red paint or nail polish, and enough gas to completely fill your tank. Although the calibrated gauge will not be as sophisticated as the trip computer in your tow vehicle in calculating the Distance to Empty, it is a lot more useful than the original gauge.

How many times have you stopped at an intersection and had to make the decision; should I turn here and go 10 miles out of the way to get gas, or should I continue on the 30 miles and hope I have enough gas? You look at the gas gauge and it says there is ¼ tank. You do a quick calculation and decide a ¼ of the 10-gallon tank should be 2½ gallons. Knowing you average about 10 miles per gallon, you think there is no way to make it the 30 miles to your destination without getting some gas first. So, you make the 10-mile detour to the gas stop. You fill the tank and look at the pump….. what the…. it only took 6 gallons to fill the tank. That means you really had about 5 gallons remaining at the intersection instead of 2½ gallons you estimated, plenty of gas to make it to you destination without this detour for gas.

Some of the manufactures fuel gauges are off even more than this example. I have performed this calibration on my last three sleds and if nothing else, it gives me piece-of-mind at those intersection stops. None of the three were accurate. The worst was my 97 ZR580, it still had 2 gallons of gas when the gauge was well below empty but still wiggled when I rocked the sled. If the gauge stopped moving I knew it was time for gas.

The easiest way I have found to perform the calibration is to start with an empty tank. You don't have to worry about emptying every last drop of fuel. In fact, it is better to leave at least ½ gallon in the tank because the fuel pickup will start sucking air before the tank is completely empty. Following are the steps for the calibration:

1. Drain the tank using a siphon hose. Leave about ½ gallon of gas in the bottom to allow for the fuel pickup height.
2. Add precisely 1 gallon of gas to the tank.
3. If your gauge is built into the cap, reinstall the cap.
4. Use paint or nail polish to mark the gauge position and label it with number of gallons if you like.
5. Repeat steps 2-4 until the tank is full.

The factory markings on the gauge are usually not close. click for larger image

Using the earlier trail intersection example, you would have seen that instead of having ¼ tank left you actually had nearly 5 gallons of gas left in the tank. Again, with a quick calculation you know you can go about 50 miles at an average of 10 mile per gallon. This would be plenty of gas to travel the remaining 30 miles to your destination.

My 2002 ZL800SS has a gauge built into the tank and has a much smaller range of motion than the gauges shown here. For that case I marked the gauge every two gallons to avoid having marks too close together. The result is the same; at a glance I know exactly how much gas I have in the tank. And without too much brain strain I can accurately estimate how far I can go before needing to get gas.