What they told you is B.S. in my opinion.
The distance remaining to empty can and does vary. The reason that it varies is because each time that the low fuel warning is triggered, it makes a new calculation based on the fuel consumption rate at the time that the current low fuel warning was triggered. If the fuel consumption rate is different from the last time, the calculated distance to empty will vary accordingly.
The low fuel sensor is a thermistor. All it does is sense whether it is submerged in fuel or not, and send that information to the computer.
The amount of fuel that is remaining in the tank when the sensor is exposed to air is a known fixed quantity. Based on the current fuel consumption rate at the time that the sensor is exposed, the computer calculates the distance remaining to empty for that amount of fuel. From that point on it is a mathematical calculation based on distance traveled and the current fuel consumption rate. If the fuel consumption rate significantly increases or decreases for a long enough time/distance interval, the computer recalculates the distance remaining to empty based on that new consumption rate.
When enough fuel is put in to the tank to submerge the sensor again, regardless of whether you fill it or not, the computer will make the same calculation again the next time that the sensor is exposed to air. It will base that calculation on the fuel consumption rate at that time.
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I agree with your logic.
I'm a Master Electrician, and understand stuff with "Sparkles".
Using a thermistor as the fuel level causes inherent reliability issues simply due to a thermistor's function as a heat sensor.
Which means it detects the liquid level as low when it is no longer submerged in the cooler petrol compared to the warmer ambient heat.
How this is processed by the I/O is probably a simple yes or no, compared to a 4-20ma current or other sensor comm methods.
I'm not even going to pretend to understand the C+ logic, and it doesn't make logical sense that running down a reserve tank would reset the parameters based on the sensor type you described aside from use and that previous tanks avg MPG.
Nonetheless, I am convinced of the effectiveness.
Yes of course there's some fuzzy logic based on operational conditions.
That said, if I don't let the reserve tank run out every so often I seem to get intermittent and sporadic results.
Most of my trips are 70 miles one way with a cruising speed around 80-90mph and traffic density determines the amount of lane splitting required.
With an accurate reserve indicator I can squeeze out two round trips.
Without "resetting" the reserve it goes into low fuel mode 40-50 miles early.
Call it superstition, I won't walk under a ladder unless I will be able to go under another one before the end of the day, because it has to balance out to even. And yes, there are a couple more, but that works for me....lol
Armed with previous trip knowledge, I have continued to run on the reserve well beyond the initial 40ish miles remaining indicator
It is in the top tank.
Some people have taken the sending unit out and successfully fixed this problem by gently cleaning the contact strip that the float uses to indicate fuel level.
I had the same problem. I filled the tank with fuel and a higher than recommended dose of SeaFoam. I did this at a time when I knew I wasn't going to be using the bike for a week. I let it sit for a week so the and then burned out that tank of fuel. I refueled and added a high concentration of SeaFoam and let it sit again. After I burned out the second tank of fuel, I refueled and added the remaining SeaFoam from the two bottles that had I bought. That was years ago and it has never occurred again. I think I got lucky. The SeaFoam must have dissolved some varnish on the sending unit that was causing the trouble.
Just learned something new.
I'll try it as the never seen two bar indicator has been a frustration for me as well.
Thanks
I'll have to check out the book.
"When all else fails" an ***** like that, instructions can be useful