Gas gauge drops as speed increases

[Guest]

It is an 82 GS1100E. This is a strange thing, as the speed goes up the gas gauge drops. At 70 MPH it reads 1/4 lower than sitting still. If it is topped off and reading full sitting still, at 70 it reads 3/4. You can watch it drop as the speed goes up.

[rustybronco]

When did this problem start. How long have you had the bike?
Have you checked the charging system voltage when the problem occurs?

[Red1100E]

I have had it for 20 years, I haven't checked the voltage when it happens. I guess I need to strap my fluke on it and go for a ride, or just check it stationary.

[chuck hahn]

All mine seem to do it and I attribute it to the air rushing thru the back of the gauges and cooling the bimetal strip that actuates the needle itself. Slow to a stop and it reads correctly again. But my drop is maybe 1/8 of a tank at the most. Ive learned that its just an indicator thats "relatively close" and not like a cars as far as consistant accuracy.

[Red1100E]

All mine seem to do it and I attribute it to the air rushing thru the back of the gauges and cooling the bimetal strip that actuates the needle itself. Slow to a stop and it reads correctly again. But my drop is maybe 1/8 of a tank at the most. Ive learned that its just an indicator thats "relatively close" and not like a cars as far as consistant accuracy.

It will go back up as soon as I slow down. When I speed back up it drops. I am going to check the charge voltage at speed and see what it looks like.

[Red1100E]

Update

14.6 volts at 70 MPH, stock gearing, at an idle 12.5 volts, at 2500 rpms, 13.5 volts. Does it sound somewhat normal for a GE1100. It has an AGM battery in it, it's about 10 months old. The battery is made in Vietnam, a little scary, but it cranks it over good.

[hjfisk]

It make sense what Chuck has said, My gs1000 Gs gauge did the same thing and I hadn't really paid it much attention ,but then I realized it doesn't change as much with the fairing on the bike. You could try blocking airflow some how and see if that made a difference. Also agree they are not very accurate.

[BigD_83]

My 650G does the same thing and I have no charging problems whatsoever...it's funny, because it looks like it is just sucking the gas back, like a big yacht.

[rustybronco]

Neither of my '850's did it and I can't fathom them being from the factory that way either. I could be wrong but it just doesn't make sense. Vehicle owners would be up in arms if that were the case today.

[storm 64]

When I fill up the 81 1100 the fuel gage moves all the to empty. When I get to about 1/4 tank it reads normal all the way to empty. Yes I ran out of gas a couple of times but that's a whole other story...

[rustybronco]

That's the result of a break in the fuel tank senders resistance wire.

[gearhead13]

When I fill up the 81 1100 the fuel gage moves all the to empty. When I get to about 1/4 tank it reads normal all the way to empty. Yes I ran out of gas a couple of times but that's a hole other story...

HUH?
Maybe your sending unit needs to be looked at

[Red1100E]

Gas gauge problems

My 650G does the same thing and I have no charging problems whatsoever...it's funny, because it looks like it is just sucking the gas back, like a big yacht.

The same here. I started to say that I don't have any charging problems. I will say I don't have any I know of. I was thinking that a resistor, in this case the variable resistor in the tank. Will draw more amps if the volts go up. There is a formula amps=volts divided by resistance. You can calculate the amp draw with that formula, and when the volts climb so will the amps. I am wondering if the increased amp flow at higher RPM's makes the gauge drop. I need to test it sitting still and see if the gauge drops with voltage rise.

The wind is interesting, I cant figure out technically how it would change the reading so consistently, but I have learned to never say never until the fat lady sings. I am going to dig into it more, and I will post what I find.

[BigD_83]

That'll be interesting to see where you get to...since I installed my new R/R, my charging numbers are consistent above idle, so I don't think that increasing Voltage output with RPM is the gremlin in my case.

[rustybronco]

I am wondering if the increased amp flow at higher RPM's makes the gauge drop. I need to test it sitting still and see if the gauge drops with voltage rise.

The voltage 'should' be stable above 2500 rpms so I doubt that's the case in this instance. Voltage reduction caused by corroded connections resulting in a current change? BUT only at speed? most curious indeed.

Clean the all connections in the fuel gauge circuit and try it again.