1981 GS750L Fuel Gauge: Reading less than is actually there

[Guest]

Hey folks,

This morning, my fuel gauge indicated I had 1/4 tank left. I pulled into sheets and pumped 1.5 gallons into the tank before it was full. I'm not sure of the exact capacity of this model's tank but it seems like the gauge may be reading less than what is actually there.

Can anyone tell me the exact capacity on this bike? What would cause a low reading on the fuel gauge?

[Steve]

No idea what the tank capacity is but I would guess it's between 3.5 and 4.0 gallons. When you hit REServe, you should be adding between 2.5 and 3.0 gallons.

Does your gauge have a red section at the bottom? Mine does, and I like to calibrate the gauge so that it hits REServe about the time the needle moves from the white section to the red.

To calibrate your gauge, you will need to remove the tank (if it's mostly empty, it helps a LOT), then remove the cover over the fuel level sensor. Since yours is reading a bit low, bend the arm DOWN a bit, maybe about 1/2 to 1" and re-install it in the tank. To check your work, put a hose on the petcock and run it to a gas can beside the bike. With the petcock in the RUN position, apply vacuum to the petcock so the fuel flows into the can. When it stops, turn the key ON and look at the gauge, if you haven't had the key ON all the time, so far. You can pull the LIGHTS fuse and turn the kill switch OFF to minimize drain on the battery while doing this.

If you don't like where the gauge is when the fuel stops, turn the petcock to PRIme to finish draining the tank and do it again. Might take two or three tries, but you will be happy with the results.

.

[80GS850GBob]

From what I've found, the lone year '81 750L had a 4.8gal tank with .5gal reserve.
Your best bet is to check the ohms readings when the sender is out of the tank. 0-120 ohms {I think} is near empty{reserve} to full. If it's a stock sender you can, as Steve said, bend the float arm to tweak it in range again and to do that you'd have to remove it anyway.

[80GS850GBob]

Oh yeah, source for my info, link-

http://www.suzukicycles.org/GS-series/GS750.shtml