Fuel gauge and warning light

[chocker]

I undertsand what your saying but when I am at about 200 km the fuel gauge is showing at empty and the low fuel light comes on. I then tried to ride it a little longer without going to reserve and it started to sputter. I then switched it to reserve and it continued. I didn't want to take a chance so I filled it up. Therefore I am only getting about 200 km or so one a tank of fuel.

Mark

[flips]

Hi Chocker.

Here are some pictures of a fuel sender from  an 86 fj1200 showing the sender in a "close" approximation of where it sits inside the tank.I don't know if this sender unit has been "adjusted".Its out of a spare tank I got for the cap.The top of the green tape line shows a "close" approximation to the bottom of the tank.Assuming that there is no serious malfunction of your sender unit you should be able to lower the float level by gently bending the lower stopper for the float arm outwards, and the low level sensor (small metal can with the yellow wire in the top) down by gently bending the arm that holds it.

Float level at empty....


Float level at full....


a bit closer...


You might try holding the sender up next to the tank while adjusting the levels.Having the sender out will allow you to check the resistance through the whole travel of the the float arm.Also plugging the sender back in while its out of the tank will allow you to see the relation of the float level to the fuel gauge so you can adjust appropriately.
Hope this helps.

Cheers

Jeff P

[flips]

Allow me to correct myself......b4 everyone else does....
Probably better to bend the the float arm itself rather than the lower float arm stopper.
Sorry about that.

Cheers

Jeff P

[chocker]

Thanks for the pictures and the advise Jeff. Is it hard to remove the float from the tank? I removed the tank once before but I titlted it too much and ended up with a nice amount of fuel on my shirt and floor. That sucked. Can anyone tell me the best way to remove the tank without all the hassle of the fuel going all over the place. I figure at least try it when the tank is low but then I would have to wait until then and the weekend is coming so that's a good time to do it.

Thanks,
Mark

[flips]

Hi Mark.

If your tank still has a good amount of fuel in it you will have to syphon out as much as you can into an appropriate clean fuel container so you can tip it back in after( NO SMOKING !).Bear in mind your not going to get it all out.Once the tank is fairly empty you can remove the tank.In theory no fuel should leak out unless you tip it upside down or the petcock is leaking.Is your bike an early model?.If you have the petcock with a tap with a "prime" setting you could empty the rest of the fuel out on this setting.Also,if your bike is an early model you might wanna check this thread out.

http://www.fjowners.com/index.php?topic=3265.0

To remove the sender,stand the tank up on its end,bottom facing you,fuel sender to  the top (lean it against something that's not going to damage the paint eg card board,old towel etc,or get a helper to hang on to it for you).You may have to peel back some of the heat shield to free up the wires (you may have to stick it back down with some contact glue after).Then its just a matter of removing the four screws and gently  prying the rubber gasket free and guiding the float arm out.Hopefully none of the screws are stuck (Use the right size screwdriver.One of mine was a bit stuck but came out with a gentle tap with an impact driver).Once you get it out you could tip the remainder of fuel out of the sender hole in the tank into your fuel container via a large funnel.When I re installed the sender I applied a thin layer of gasket silicone to the rubber gasket to prevent possible leakage.After all,the gasket is 25 years old!

Hope this helps.

Cheers

Jeff P

[chocker]

Thanks for all the information Jeff. When I remove the pedcock I will install the wiring. Just wondering since I have an 86 fj1200 I shouldn't have to worry about fuel leaking out of the pedcock when removing the tank since there is no vacuum opening the valve? Also I guess after I bend the sending unit, I have to put it back on the bike and test with half a tank (12 litres) then try again if it's not synced correctly. Is there an easier way than that?

Mark

[flips]

Hi Mark.

If you disconnect the main fuel line off the petcock and no fuel continues to leak out your petcock is OK.There is a small o'ring and spring inside which can eventually fail causing it to leak when there is no vacuum connected.
Unfortunately when adjusting the float arm its going to be a "Best Guess".Have a good look at it when you pull it out,plug it into the bike and see what the gauge reads when the float is all the way down and incrementally and slowly raise the float and see what the gauge does.If the gauge raises relatively proportionally to the float arm the sender is OK and just needs adjustment.Bare in mind the fuel gauge has a heavily damped movement to stop it from jumping around as the fuel sloshes around in the tank and moves very slowly.
It might pay to get a piece of paper and trace the position of the float in the fully down position before you bend the float arm/warning light sensor.Put a line of tape along the side of the tank marking where the bottom of the tank is like I did in the picture and hold the sender up to the side and using  the tape as a guide.You will want to try to have the bottom of the float roughly 20mm off the bottom of the tank when fully down.Trace the position of the float again for reference in case you think you need to do it again.
When you get it all back together fill it right up,reset the trip meter.You should quite comfortably be able to go 250km without fear of running dry and see what the gauge reads.Should be getting very close to reading  empty.Then fill up again and see how much fuel goes in.This will give you a good Idea on whether more adjustment is required using the traced float arm positions as a guide.
This is how I adjusted mine.I did it twice.I get similar mileage to Arnie and James.I am not aware of an easier way but a more knowledgeable FJ'er might chime in.Plenty of very knowledgeable FJ'ers here that's for sure!

Hope this helps and have fun  

Cheers

[SlowOldGuy]

Is there an easier way than that?

Actually, there is an easier way.  Motorcyclists have been doing it for generations.

Figure out how many miles/km you get per tankful and use your trip meter to track it.  May take a little mental arithmetic, but it will probably be more accurate and reliable than the gauge and light ever will be.

DavidR.

[chocker]

I will definately keep all that in mind. If the petcock starts to leak, what do I need to do to fix it. Can I just replace the O-ring and the spring or is it more complicated than that. I am going to install a new fuel line. I will remember what route it takes so that it won't get kinked. I am going to wire up the petcock as well so that the 90% angle joint will not fall off just in case. I am going to replace the spark plugs as well because they are looking pretty old just from the outside (rusted) and since I'm there I will change them. Any ideas as to what spark plugs to use. Good quality but something that won't break the bank either.

Thanks,
Mark

[chocker]

To reply to David, I do rely on my trip meter but since the sensor shows as empty the bike stalls and I have to switch to reserve when it's not really empty to start with.

Thanks,
Mark

[flips]

Is there an easier way than that?

Actually, there is an easier way.  Motorcyclists have been doing it for generations.

Figure out how many miles/km you get per tankful and use your trip meter to track it.  May take a little mental arithmetic, but it will probably be more accurate and reliable than the gauge and light ever will be.

DavidR.

Hi David.

Yes you are right.Using the trip meter track fuel consumption is a good method and I did not mean to suggest otherwise.I was just trying to help Mark get his fuel gauge to read empty when there's approximately 1-2 litres left in the tank rather than the 4-5 litres it is currently reading.Is there an easier way to calibrate the fuel sender?

Cheers

Jeff P

[SlowOldGuy]

Sorry, I forgot about the stupid "stall the bike" logic on some models.  But wait, you've got an '86?  If you want to stop the "reserve function," just unplug the electrical connector on the petcock. 

It won't help you gauge reading, but it should stop the stalling/reserve switch issue.

You can replace the o-ring in the petcock.  It should be a 5mm OD x 2mm cross section.  Carefully disassemble the diaphragm (don't tear it!) and you'll see what to do.

Sorry Jeff, didn't mean to side-track your good advice.

DavidR.

[flips]

Hi David.

No apology required.Just trying to help a fellow FJ'er out,same as you ! 

Cheers 

Jeff P

[chocker]

Forgive my ignorance, I know what an O-ring is but 5mm OD means outer diameter and the 2mm is the inner? Would I be able to find this at most hardware stores or only a motorcycle dealership?

Mark

[SlowOldGuy]

2mm is the cross section thickness of the o-ring