... this bike really has a 1 gallon reserve?
That is what it's advertised as, I have not verified it personally.
If you would like to have some peace of mind, why not measure the tank and do a fuel gauge calibration at the same time?
Do this in any order that makes sense to you.
Drain the tank completely. Take the tank (either on or off the bike) to the gas station and fill it up, you will see what it actually holds. This is "total fuel capacity."
With the full tank on the bike (and the bike on the centerstand), run a fuel hose from the petcock into a catch tank of sufficient size (4 gallon minimum). With the petcock in the RUN position, apply a vacuum to the vacuum port so the gas will flow. Do not use the REServe or PRIme settings for this. Turn the ignition key ON, watch the fuel gauge. Note where the gauge needle is pointing when the gas flow stops, that is where you will need to flip the petcock to REServe.
Move your fuel line to another container, move the petcock lever to PRIme. This will draw from the same place as the REServe, but will not require any vacuum for it to run. Measure the amount of gas that came out this time. This is your "REServe capacity." Note your gauge needle at this position, too.
Ideally, you should take the bike (or the tank) AS-IS to the gas station and fill it again. There is a possibility that there is a small amount of gas left in the tank, but that won't come out while you are on the road, either, so you will now have an idea of your "useable fuel capacity", which might be just a little bit less than your starting "total fuel capacity".
The difference between your "useable fuel capacity" and your "REServe capacity" will be your "main fuel capacity".
If you would like to adjust where the needle is pointing when the main tank runs out, that is easy to do. Just empty the tank, remove the sending unit, bend it up or down to adjust the needle. Reinstall the sending unit, add enough gas to get it over the REServe point, test it again. Personally, I like to have the needle right at the transition from white to red on the gauge. That way, if it's in the red, I know I am already on REServe. If you adjust your float, you should also note the new position when the tank is empty, then compare that with where the needle is pointing when the key is OFF, so you know the difference.
Yeah it's time consuming and a bit fiddly, but you only have to do it once (per bike), and makes it so much easier to KNOW what your fuel level is and when you will be approaching the REServe mark.
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