I replaced the original speedometer on my 2010 Dyna Super Glide with the HD upgraded model. This one has an analog tach, digital speed readouts along with multiple odometer/fuel readouts. It is very accurate, I have calibrated it numerous times with different GPS' and radar displays and speed and mileage is spot on.

The tank is 4.7 gallons and I get the reserve "miles left readout/warning light" at .7 of gallon left and it always initially displays 32 miles remaining. Today I deliberately let it get down to 11 miles remaining before filling up and it took 3.7 gallons. Obviously there was a gallon {mas y menos} still in the tank and that would translate to more like 40-45 miles left, not 11. The analog gauge on the tank itself always shows me out of fuel well before the speedometer display.

I try to ride on the top half of the tank when possible but out here in the west it can be a long way between fillups. I consistently get 44/45 mpg riding solo on the two lane state highways at around 60-65 and closer to 42 if I am blasting down the interstate at 75+. Have no desire to run out some day but it sure seems like both of the gauges are lying. WTF?

 

I wouldn't expect any gas gauge on a motorcycle, expecially, to be accurate enough to be exactly out of gas when the counter goes to zero.
On the limited, I have 6 gallons. Typically I start looking for a gas station when the warning light comes on- and it usually takes around 5 gallons to fill.
What I don't know is how much of the remaining gallon or so I can rely on. I usually get around 45 mpg. more or less, but having the needle on E and the warning light flashing bugs me enough to not want to run out miles from a gas pump.

I think that's about as accurate as you can expect, and it wouldn't surprise me a bit if they didn't calibrate things to be a bit on the conservative side. There is always the option to carry extra fuel just in case.

My speedo is off too, which is also very common on motorcycles. by about 10 mph or so at 70 mph, base on what those radar trailer things tell me when I ride by them.

 

I had the same issue with my 2018. The website and owners manual states the tank hold 6 gallons. If I ride it down to as empty as I am comfortable 5 miles on the reserve readout, the most I can put in it 5 gallons. I spoke to the service rep two weeks ago about this very issue. He said the tank would hold 6 gallons if it weren't for all the "stuff" in the tank. He said with a 6 gallon tank, after 200 miles of riding you better start thinking about filling up. My light comes on with 65 miles on the reserve readout, with 25 miles on the reserve it reads "Low Fuel" I think. On another note, when the tank is full up to the neck, the reserve reads 276 miles everytime. I average 40 Mpg, I have a hard time staying off the throttle. Especially on the highway with the cruise set on 65 or 70, If I come upon an 18 wheeler I roll the throttle wide open.

PS. We seem to have an abundance of 18 wheelers everytime I ride on the freeway.

 

I almost think the miles to empty is more likely a "miles to reserve." Then you probably have a gallon-ish left before you're empty. I wouldn't doubt it if it were designed that way as a buffer, either to allow an error percentage with the gauge itself or to account for people who figure they want to get the tank as low as possible and then blame the bike when they're stuck on the side of the freeway.

 

Many years ago my gauge would read Empty no matter what. I took it in to be repaired. Then it never left Full.
So for about the last 13-14 years I've always reset the trip odometer when I fill up. Last year I got a new tank and complete paint job. Didn't bother to waste time with a gauge, I just put a flush mount fill cap on that side. Now both sides have the same cap and I can fill from either side if I like as it's not actually a split tank like the old style tanks were.
I've never met anyone yet who thinks their gauge is remotely close to accurate.

 

Thats what I thought. I was thinking it was how many miles to reserve initially, just never took the chance. I guess the only way is to run it dry and see how much you can pump in at that point. My gauge was replaced under warranty early on, it was way off. The one now is accurate, when that light comes on its close to Empty. This rep assures me a 6 gallon means 5 gallons of gas.

Its all been discussed here. Everyone has a different experience.
https://www.hdforums.com/forum/touri...yea-right.html

 

Thanks for the link. I browsed it quick and noticed a couple guys who ran out of gas completely and still were getting different volumes for a full tank. 5.4 one guy, 5.7, 5.9 another, etc.

Also another interesting point from that thread is how they're being filled up. For example my road king that had the gas cap on the right side, was always filled when it was on the kickstand. My RG, with the cap in the center of the tank, is still filled on the kickstand. I think if I stood my RG straight up I could fit more gas in it. I'm sure there is air trapped in there somewhere, it's kind of hard to "burp" these bikes and fill them completely.

As for the rep - 1 gallon is a pretty decent volume for "stuff" in the tank. I've never seen the inside of my fuel tank, but I dont know, that seems like a huge amount of stuff.

The other thing is the digital readout miles to empty, from what I gather, is calculated by the ECU based on current riding conditions. I've noticed when I'm cranking hard keeping the engine under load, the readout drops a lot. Hop on the highway and cruise, miles to empty increases. Computer sees casual cruise and realizes you aren't burning as much fuel as you were before and will have a longer range.

Miles to empty gauge gives you a range based on the data somebody inputed when programming the ECU. At that point, the computer is dealing with expected MPG vs real MPG. If you're getting better real MPG than what the computer is expecting based on data its receiving and analyzing, for whatever reason, you'll have a discrepancy between the digital readout and real fuel in the tank.

 

One of the joys of starting out on a Sportster, is you dont use a fuel guage, you do the math of the trip meter. How many miles on a tank of gas. but either way you are still using a guage...

 

I've ridden mine about 10-15 miles past where it says 'Lo'.. ended up putting 5.9 gallons in.. don't want to do that again though!

 

Very good points. I've never ridden it that low. I always pump till the pump clicks off. Topping off I always splash gas on the tank. I have one of those 1 gallon gas containers made to fit the corner of the saddle bag. Just never felt safe riding with gas in there.