Can someone explain to me what is meant by left side fuel gauge? I want to install a gauge to have a constant fuel reading.

 

Hi from the UK and welcome to HDF. What year is your bike, that will help us give you an answer? AFAIK your bike doesn't have any means of providing a reading to a fuel gauge, however H-D does sell a speedo with integral fuel gauge, which it is worth checking out. Go to the H-D website and the Shop tab, where you can find details and fitting instructions. They include adding a device that may be suitable for a separate fuel gauge.

 

I find it easy to just track my mileage, I know when I hit around 60 miles on my 48 the fuel light is about to come on.

 

Yes, same here on my Custom. Larger tank, but I know at about 120 miles or so the light will come on. Later if it is mostly highway miles. That said, on a 4.5 gallon gas tank my custom light usually comes on at about 2.4 gallons used so at least 2 gallons left. I could easily go +160 miles on a tank and still have a gallon left, but I usually top off before that.
Some day, I'll try and go 190 or 200 miles on a full tank. I do get 50 to +51 MPG on road trips at 55 to 65 MPH so that should only be 4 gallons. Of course, wind and hilly roads can make it less.

 

I think the term "left side" refers to the big twin tanks with two caps, right side is for filling up and the left side is just for show and can be replaced with a fuel gauge, that wont work on your bike.
I agree with the others that just using the trip odometer is the most reliable method of keeping track of fuel level.

 

That, ain't gonna happen.
Harley fuel gauges are more of an off/on, go/no go, than a rheostat.
An odometer has been the tried and true fuel-remaining gauge, for decades.
883 motor, 50 MPG (depending on your wrist/throttle action), 4.5 gallon tank. 165 miles to reserve, 200 miles until emergency. 230 miles, to critical (walking/hitch-hiking towards the horizon).
I eliminated the fuel gauge, residing in my Softail's "left" tank, because it was fugly/nontraditional, and, worse than being an eyesore, worthless.

 

Don't forget the original fuel gauge, a stik with notches carved for each gallon, wasn't as reliable though because you might loose the stick!
Also lots of early bikes had a sight glass on the side of the tank.

 

https://www.harley-davidson.com/stor...gauge-kit#tabs

https://www.harley-davidson.com/stor...900274--1#tabs

 

Right. I know about those, but, I imagine they're similar to other Harley fuel gauges. Not very accurate. Just my $.02. God love 'em if someone has one and likes it.

 

The one in my digital speedometer works just fine and is fairly accurate.