My dads 85' Honda Nighthawk has one and it lies from time to time. He has ran out of fuel once when the gauge said he still had a half a tank left. Lucky, the RES tank does come in handy for this kind of situation.

 

Yeah i usually do use the trip meter, but i just upgraded to stage 2 Jetting so now im using more gas.

 

I would have to side with Highbeam on this one, more fuel per mile is used when off roading.
Off road you are always on and off the gas. Hitting the throttle like that uses more gas. To a smaller degree you will spin your rear wheel some when offroad, and that helps lower your mileage.
Either way, 09 you need to use the trip meter and find how far you go until reserve. Use that as a yardstick. If your bike hits reserve at 80miles regularly, you could think about filling it up when the trip meter hits 75 or so. I figure my reserve is about .4 gallons, that should take me about 20 miles after I switch to reserve. I wouldn't stretch the reserve that far but it's plenty to get you to the next gas station unless you are waaaay out in the woods.
I do like Deej and keep a couple 5 gal cans of gas at home and during the summer months fill the bike with those.
Dan

 

I use trip meter as well. I can also attest to more gas is used riding off-road than on. On road I putt-out around 65-70 miles on the ODO. Off road, I've had it as low as 45 and 50 miles.. I'm guessing because off-road I drive it like a hoon, WOT down the trails getting sideways.. hahaa...
On road you're at a constant (usually 6th gear) the majority of the time.

 

To me off road means off road, never leave 1st or second, lots of gas and brakes. Real trails with switch backs and mud holes. This bike is a real fuel hog off road.

My XR400 had a 2.3 gallon tank, 1.7 to reserve, and weighed 300#s just like the KLX. The XR easily ran a 65 mile short course enduro without hitting reserve. The KLX has a 2 gallon tank, 1.6 to reserve and couldn't make 45 without switching to reserve. Maybe as it breaks in it will do better? I hope so because I don't really ever want to depend on the reserve for a normal short course ride.

I sort of thought a modern 250 would be easier on fuel than an old school 400.

 

My bike new and broke in got 69 mpg on combined riding I never went through a whole tank either on or off road alone. With the slip-on and the jetting with the snorkle removed I still get 60-62 mpg in combined riding but I'm not a beast off road as I'm too damn old to nurse for a big get off like I used to.

 

I always used the trip meter and carry some extra MSR tanks if I need to go on an extended adventure where gas supply may be unknown.

I know it would be expensive to make a gauge with a sender unit and the associated electronics. I wonder if somebody could make one like they make in a lawn mower tank. Sort of like:



The float displaces a needle, its a real simple design, but I believe this would only work in a square tank where the level is linear. It may or may not work (or at least be super accurate) for a motorcycle tank where the tank design has wings and little areas for the fuel to hide, plus the gauge itself would have to be a little bent to get to the bottom of the tank. I'm sure if it were easy and cheap to make a gauge, Kawi would have put one on??

 

when i went from a 250 to 351 my fuel usage off road increased a little, havent had it on road long enough to compare.

that hard off road very rare to be below 6500rpm and most of it at full throttle

 

Some GPS units have them but it's still based on miles.

 

Those cap gauges are used on snowmobiles, fairly accurate on 12 gallon tanks but not sure they would reach deep enough into the klx tank? On down side is when you pull the cap you bring a lot of dripping fuel with it (unless your empty).

I wanted one for my generator and found: http://www.kelch.com/html/products/p...gory.php?cid=2 had them in all shapes and sizes and made them for just about everyone.