low fuel indicator today

[Max]

had the red flashing (led?) low fuel on the CM the first time and zero bars on the gauge. Ok, so we're cruising around Hershey PA, when the warning led comes on. Usually adamant about topping up, more so on marathon runs. Scenery slipped by, guess it was bound to happen. Didn't think anything of it at the time.

 

Have a couple of questions and not a lot of time to research at this point. The reserve petcock on. Is the 1.06g/4L reserve tank separated from the 5.3g/20L main tank capacity for a total of 24L? Does the LED normally operate at the point where the main tank is nearly empty and requires switchover to reserve?

While on topic, also noticed since day one, the ratio of gas gauge level bars isn't anywhere close to the actual amount of fuel in the tank. Gotta live with that I guess.

You'd think an owner should know these things.

[videoarizona]

 

That depends upon your definition of "separated"! But no...it's all one tank. The reserve pick up is a lower height tube than the normal pickup. So you are now able to access the fuel closer to the bottom of the tank.

 

>

 

That question can also be up for debate. All bikes seem to behave slightly differently with regard to the number of bars and quantity of fuel. The owners manual only says 1.1 gallons is left when the light comes on. How accurate that is depends upon your bike and how accurate your gauge "seems" to be.

 

Recommended that you grab a spare gas can, fill it and ride until the bike dies on reserve. Calculate your miles while on reserve so you have an idea. If the mileage is close to what you normally get in a gallon of gas, then your gauge is pretty close.

Hope this helps.

[utadventure]

There is only one tank on the bike. The difference between the "regular" and "reserve" tank is that the reserve setting can access the bottom part of the tank.

 

Each warning light is a little different. After you get the warning light and fill the tank shortly thereafter, you'll know pretty well how "your" bike does.

 

My '86 typically hit the warning light when the bike had used 4.3 gallons of fuel. That leaves a gallon to go. I usually get 32-35 mpg on the bike and so I knew if better fuel up within 20 or so miles of when the light came on.

 

Go ride and learn how your bike works.

 

Dave

[frankd]

The tank holds 5.3 gal. (U.S.) total. I'm sure all the gas gauges are a little different, but both my 83 and my 89 use about 4.0 gallons of gas when the red reserve indicator comes on, leaving 1.3 gallons in the tank. On my 89, the first bar goes off at about 53 miles, the 2nd bar about 70 miles, the third about 90 miles, the 4th about 108, the 5th about 135, and reserve comes on just before 170 miles average. I usually get about 42 MPG.

[Max]

Appreciate the detailed posts. I'll be keeping a closer eye on things. Definitely have to figure out sequential mileages at fuel gauge levels. Intend to keep the bike around a few more years. That also clears up a couple of misconceptions I had about the reserve tank and such. I'll try the run dry to reserve and check remaining mileage, on return. (and remember the gas can)

The only mileage I checked last summer over an 8500 mi. run, 2up, primarily interstates, averaging close to 45 US mpg.

[Venturous Randy]

I, like many 1st genners just leave the valve on reserve all the time. For me, with monitoring my mileage since the last fillup, the easy to read bars, the blinking light and also knowing I have at least 50 miles once the light starts blinking, reserve all the time works for me.

Also, with the difficulty of changing the valve while riding, I would not want to chance having to change the valve in traffic. I also would not want any accumulation of trash in the bottom of the tank over a period of time.

RandyA

[jdross440]

The "tall" tube (main supply) in my tank has come out of the petcock and just laying in the bottom of the tank. It is too much trouble to take it apart and reinstall it. Therefore when the low fuel light starts blinking I know about how far I can go.

[icebrrg3rd]

'83 didn't have the reserve switch...

 

On mine it works like this:

-full tank thru 1st gal - all bars on

-for gal 2-4 - every 1/2 gal used one bar goes out

So by the time all the bars go out and the light flashes, I'm down 4 gallons so I have about 1 gal left, so figure on gas within 25-40 miles dependant on highway/city use.

 

-Andrew

[dvuch1]

I leave mine on reserve all the time. I usually fill between 110-130 miles to avoid problems and I'm generally wanting to stretch a bit by that time. My 2cents.

[Venturous Randy]

Filled up today with the red light blinking for about 20 miles and the trip odometer reading 190 miles and it took 4.3 gallons to fill up. Not bad for a 166,000 mile engine and a V-Max rearend

RandyA

[jasonm.]

yes one tank not 2 as many state. The fuel sender can be calibrated by removal and bending the float arm. When my light comes on and stays on...I have exactly one gallon. Also most do not realize they are not truly filling the tank on a 1st gen.. You can squeeze in another 1+ quarts if you let the fuel settle and fill a bit more. I can consistantly run ~ 180 before the reserve light come on. And this is hiway at 75mph. Much of this is due to my going completely thrru the carbs a few years back. No mods just new floats. Ethanol with water is trashing your floats.

[GilbertHall]

I read once the warning light blinks and when the light stays on constant, you best be close to the gas station.

[videoarizona]

My results from last weekend's 400 mile run.

 

50 miles - lose first bar

70 miles - lose 2nd bar

90 miles - lose 3rd bar (half tank)

110 miles - lose 4th bar

130 miles - lose 5th bar

150 miles - lose 6th bar

Reserve light comes on.

 

Averaging around 42.6 mpg.....so with approx 1.3 gallons left....I should be able to safely go between 30 and 40 miles after light comes on before I coast to a stop. Or crud up carbs with tank debris!

 

Also...if I have high winds or lots of hills, the first bar will drop off around 40 miles. If I then watch....the rest of the bars drop off at 20 mile intervals. So my gas gauge seems linear in that respect.

[Guest Greg W]

Reading the posts about gas milage. But my issue with my new/old 1st gen. Is the gas gauge will go from full bars to no bars in 5 mins at around 40 miles.

Is this common? I saw someone mentioned calibrating the gauge?

[Prairiehammer]

Reading the posts about gas milage. But my issue with my new/old 1st gen. Is the gas gauge will go from full bars to no bars in 5 mins at around 40 miles.

Is this common? I saw someone mentioned calibrating the gauge?

 

If you pull the sending unit (inside the tank), you can see the construction of the sender albeit it is enclosed within a steel enclosure. It is basically a wiper attached to a float. The wiper makes contact at various points along a wire winding. With time, the core of the winding becomes distorted, resulting in erratic fuel gauge readings. Some folks have simply straightened the winding core. Others have gently cleaned the accumulated crud from the wire winding.

Three caveats: the tank must be emptied to less than half full before pulling the sending unit out or fuel will come out of the large hole that results. Secondly, if it isn't the sending unit, check the wiring between the sending unit and the fuel gauge, especially the connectors at the sending unit. Thirdly, bad solder joints on the CMS (computer monitor) have also been known to cause similar erratic fuel gauge behavior.

http://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/vKsAAOxy0bRTDP-y/$_57.JPG

Edited June 27, 2014 by Prairiehammer

[Neil86]

You might want to test the sender resisitance first before blaming sender and tearing into tank.

Unhook connector, test between green wire and black on tank side.

Specs...

Less than 30-44 ohms for full tank.

Approx 160-180 ohms 1/2 full.

Greater than 270-300 ohms empty.

 

 

 

A no bars reading on the CMS would usually require a high resistance or open circuit on sender, the harness, CMS solder joints, etc.

[TCK04RSV]

Bugs me when the bike starts sputtering until I switch to reserve. Especially at highway speeds. Why not just run it on reserve all the time? No separate reserve tank, just a shorter tube drains the lower limits of the tank.

[Flyinfool]

On a 2nd gen you can switch to reserve while moving, on a 1st gen you have to get off the bike to make the switch, not a good idea on the side of the highway. That is why most 1st gens just run in reserve all the time and use the gas gage and blinking light. Its no different than driving your cage, there is no reserve, you just need to pay attention to the gage and mileage since the last stop.

[Max]

That is why most 1st gens just run in reserve all the time and use the gas gage and blinking light. Its no different than driving your cage, there is no reserve, you just need to pay attention to the gage and mileage since the last stop.

 

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