Fuel gauge and warning light

[SlowOldGuy]

The float drives the gauge reading.  It's just not calibrated very well.  I believe the float signal also provides the input to the reserve "logic" that cuts the fuel pump (or something) to simulate running out of gas so you will switch to reserve and start looking to fill up. 

The fuel light is a separate circuit.  You probably have to run the fuel level farther down to activate the fuel light circuit.  I know my gauge sits on empty for quite a while before the light starts to glow.

DavidR.

[chocker]

I understand what you're saying but it seems that my fuel gauge as at empty at about 200 kms. This seems pretty low as an average. At that point the low fuel light goes on a little after that. The last time it happened to me was in traffic on a hot day and the bike was giving out then died. I had to switch to reserve and continue.

Mark

[ribbert]

I understand what you're saying but it seems that my fuel gauge as at empty at about 200 kms. This seems pretty low as an average. At that point the low fuel light goes on a little after that. The last time it happened to me was in traffic on a hot day and the bike was giving out then died. I had to switch to reserve and continue.

Mark

Fuel gauges on cars and bikes have been inconsistent and unreliable forever, mine for example gives me 200 on the top half and 100 on the bottom. I like everything on my vehicles to work but I'm not too fussed about fuel gauge accuracy.  If you've nothing better to do or you're a stickler for detail by all means fix it but I find the trip odometer the most reliable or if I'm feeling flash I use the fuel gauge on the GPS with programmable fuel warning.
Reserve switches are a hangover from the days of no fuel gauge, cars don't have them.   I don't use mine.  I, like many others here no doubt, have been caught out over the years reaching for the reserve when it splutters only to find I forgot to switch it back to the main when I last filled up. At that point you re-plan your trip to include a stop anywhere in the next few hundred yards.

[chocker]

I hear what you're saying but that is not the only point as I have said earlier in this post. I am only getting about 200kms per tank of gas. I should be getting at least 300 to 350 kms on the same tank. I am not that much of a stickler but I do like it when I don't have to fill up my tank 1/3 more often than I should. It gets to be a little annoying.

Mark

[ribbert]

I hear what you're saying but that is not the only point as I have said earlier in this post. I am only getting about 200kms per tank of gas. I should be getting at least 300 to 350 kms on the same tank. I am not that much of a stickler but I do like it when I don't have to fill up my tank 1/3 more often than I should. It gets to be a little annoying.

Mark

Sorry, I should read more carefully.
Noel

[chocker]

Would anyone know what the resistance should be from empty to full for the sending unit. I would like to verify if the unit itself is faulty.

Mark

[SlowOldGuy]

I hear what you're saying but that is not the only point as I have said earlier in this post. I am only getting about 200kms per tank of gas. I should be getting at least 300 to 350 kms on the same tank.
Mark

I've been reading and I guess I'm a litttle lost at what you're trying to accomplish. 

If you're griping about only getting 200 km per tank, then you've got a CARB problem and the fuel gauge has nothing to do with it.

DavidR.

[fj11.5]

fuel gauge, isnt that the funny little thing in the top right corner of the dash that cant make its mind up  , rather rely on the trip meter,seeing as i have no reserve

[chocker]

In response to DavidR's comment, would the carbs take more than 1/3 more fuel than normal? I ask this because I undertsand that if there is a carb problem you would end up getting lower mileage per tank but this low seems to be a little extreme to me. I read that most people are getting between 300 - 350 kms per tank and I am only getting about 200kms. As I have said previously when my tank is on empty there still is a good amount of fuel left and then my low fuel light goes off. Then again it could be a combination of carb issues and the fuel sending unit. It seems to run normally with no issues and it has good throttle response.

Thanks,
Mark

[fj11.5]

check your spark plugs , if its the carbs your plugs should not be grey/tan

[andyb]

In response to DavidR's comment, would the carbs take more than 1/3 more fuel than normal? I ask this because I undertsand that if there is a carb problem you would end up getting lower mileage per tank but this low seems to be a little extreme to me. I read that most people are getting between 300 - 350 kms per tank and I am only getting about 200kms. As I have said previously when my tank is on empty there still is a good amount of fuel left and then my low fuel light goes off. Then again it could be a combination of carb issues and the fuel sending unit. It seems to run normally with no issues and it has good throttle response.

If the bike is using tons of fuel, then the devices that meter fuel would very probably be on the suspect list, y`think?

Nah, it's probably the wrong oil.  Or tires.   

[Arnie]

Mark,

Its hard to tell from your post if you're actually using all the fuel in your tank.
How many litres does it take when you fill-up?
My typical odometer readings vs fuel gauge readings are:
~150kms = 1/2 tank indicated on the gauge
~250kms = Empty indicated on the gauge - shortly after FUEL light is on intermittently
~300kms = Below Empty on  the gauge and the FUEL light comes on solid
~325kms = Bike coughs and I need to switch Reserve on
~350kms = I get nervous about running dry and fill up :-)

I did get to 400kms once, but the tank was completely dry and I ended up pushing.
(I put 21.5L into my 21L tank on my '91 FJ1200 )

Your milage and gauge readings may be different.  What the gauge indicates has NO bearing on how much fuel your engine is using.  That is determined by carb settings, gearing, wear on the engine, tire inflation, avg speed, and your riding habits.

Arnie

In response to DavidR's comment, would the carbs take more than 1/3 more fuel than normal? I ask this because I undertsand that if there is a carb problem you would end up getting lower mileage per tank but this low seems to be a little extreme to me. I read that most people are getting between 300 - 350 kms per tank and I am only getting about 200kms. As I have said previously when my tank is on empty there still is a good amount of fuel left and then my low fuel light goes off. Then again it could be a combination of carb issues and the fuel sending unit. It seems to run normally with no issues and it has good throttle response.

Thanks,
Mark

[chocker]

When the fuel gauge is at empty I go fill up. I have to fill approximately 12 - 14 litres to fill it up maybe slightly more if I really fit it to the top. I will check the exact volume next time it goes on empty but that's about right.

Mark

[tmkaos]

I think looking at these post the fuel gauges seem to be as individual as the bikes and owners themselves..

I'm similiar to Arnie

~100km  - needle hasn't moved off full
~200km 1/2 tank
~250km needle says empty, intermittant fuel light

At this point I usually drop my nuts and fill up usually 17 litres of 91 octane

I asked the "how far on a tank?" question a while back and a few guys chimed in, here's the post with info if your interested..
http://www.fjowners.com/index.php?topic=1634.0

Happy riding

James

[Arnie]

Mark,

Our bikes are getting very similar fuel economy results.  I average 17km/L.  Using your figures, 12*17= 204kms  and 14*17= 238kms.  The difference is that I normally fillup with 17-19L.  I don't think there is anything majorly wrong with your bike or carb settings.
As discussed, the fuel gauge just isn't that well calibrated.

Arnie

When the fuel gauge is at empty I go fill up. I have to fill approximately 12 - 14 litres to fill it up maybe slightly more if I really fit it to the top. I will check the exact volume next time it goes on empty but that's about right.

Mark