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Fuel gauges / lights

Discussion in 'Technical and Troubleshooting Torque' started by VTRBob, Mar 2, 2006.

  1. HI all Following Mr PNUTS idea, im going to also throw up the occasonal thread on the Technical side of things as well , or if anyone would like to know something specific i'll try to help out there as well
    ( But Vic and Dear Deb are the one to ask about the 'meaning of life' etc )

    I have noticed that we get alot of threads in "technical" about fuel range / lights and gauges . So i've put together a few basic rules to help some of you on your way.

    You have to keep in mind that ALL fuel gauges / lights are only a rough indication ...... yes some are damn accurate BUT the more technical things get the more easy they can stuff up.

    Go back a few years and most bikes had NO lights or fuel gauges, we as a rule always reset the trip meter to '0' and through doing the little test below knew we had XXX k's or miles range before reserve or running out.

    *copyed from one of Vic's posts bc im lazy :grin:

    Fill it to the top.

    Reset trip meter

    Travel 100km

    Top it up again.

    Divide km by the litres used and you have just worked out your fuel range.

    eg. 16lt tank. ride 120km top it up with 6 litres.
    120/6 = 20
    20*16(lt) = 320km tank range.

    I do this little exercise on EVERY new bike I get regardless if I have a fuel gauge / light or not and i still religiously reset the trip every time I fuel up.

    That way if the gauge is showing 1/4 but the trip meter is telling me i've done 400 k I know those two dont add up from the range test done when i bought the bike,so I start to look for a garage.
    The gauge may well be right and i've just put in a really good economical run, BUT if the trip meter is right and the gauge is wrong I just saved a long heavy push :LOL: :LOL:

    Its much easyer with the bikes that DO have a reserve switch ( as long as you remember to put it back to RUN after you fuel up :LOL: )
    More than once on my older bikes i've gone for the reserve only to find its already there..... :oops: and its not a nice feeling .
    But alot of the modern bikes its all automatic, so when you get that 1st 'cough cough' its already time to start pushing, unless you fluke it and it dies out the front of a garage !

    I hope this clears up a few things for yahs or even helps some of you newbies out .............

    :LOL: :cool:
  2. I don't have a guage or light, I just wait until the bike starts to stutter, flick it over to reserve and go find a petrol station.

    I also reset my trip meter... so I know when I'm getting close to running out.
  3. Top Tip, will do this next weekend, no warning light or fuel gauge on my machine, and have pushed the heavy bugger to a servo once before.
    Thanks Bob.
  4. I'd just like to add, calculate your fuel consumption every 4-5 refuels. You will get a good idea of how hard/soft you're riding as well as if the bike is developing and thirst problems. Always err on the side of caution. Your bike may take you 22 k/L, but treat it as 20 k/L and you should be able to get refuelled way before you run dry.

  5. Always reset my trip meter and fill at 200 even though i get 250 easy before i hit reserve that way its normally a clean 10 to fill up :)

    That is ofcourse on every day runs when I am having fun on the weekends I am lucky to make 200ks before I hit reserve

    But yes always reset the trip meter that way you cant go wrong
  6. Fuel consumption calculations

    Iv'e merged these topics together as they are basically the same content vtrbob

    Hey peeps,
    Some info here for those (particularly newbies) who want some fuel economy figures for the wittle zzr. The following procedure can also be used for anything with a fuel tank :p :grin:

    I have always been interested on fuel consumption on the various vehicles I have owned and have come up with a dead easy and accurate way of calculating average fuel figures. The main basic problem with working out fuel used/100km on bikes are the relatively small fuel tanks and shorter range compared to the average cage. If at one measurement point you are 0.5 to 1 litre out over say 1 tankfull of 280 kms this can equate to @ 6 mpg error.

    The trick is to do the measurements over a long time ....many tankfulls and many km's.

    1. Basically start off with filling your tank as full as you can (without being silly)
    2. Take a note of your odometer reading. And I also zero my trip meter (which as we know is very useful if you have no fuel gauge and don't really want to have to hit reserve in what wil probably be an awkward situation).

    3. Ride as usual..... but from now on you must make a note of how many litres of fuel you put in your bike......You do not have to fill up to the top ...I usually ask the servo for a receipt.

    4. If you want to see how you are going say after 2 tanks here are is the "real world" example of my zzr's figures.

    tank 1: Start k's = 33782 finish k's = 34037 distance 255km litres 9.88 (tank filled to top)

    Tank 2:start k's = 34037 finish k's = 34342 distance 305km litres 14.74 (tank filled to top)

    you can work out fuel consumption after this time as long as you have filled your tank up to approximately the same level as in step 1. Part filling is ok as long as you keep adding up your litres as you go....your odometer will keep track of your k's.

    5. To calculate: Take away your finish km's away from your start km's in this case 33782 - 34342 = 560km

    add all litres to get to the full tank = 9.88 + 14.74 = 24.62 litres

    so we have travelled 560km on 24.62 litres.

    to work out fuel consumption we use llitres divided by km's (measured in 100's) eg 560kms = 5.6 hundreds of km's

    which is 24.62litres divided by 5.6 hundtreds of km

    this gives a consumption of ..... 4.39L per 100km
    for those who like mpg (miles per gallon) we use a conversion factor of 282

    answer in mpg is 282 divided by litres per 100km
    = 282 divided by 4.39
    = 64.23mpg

    so as we have only basically worked this out over 2 tank fulls if the levels were 1 litre different to when we filled the tank to start and to when we filled the last tank..... our results will have quite an error.. How we get this error factored out is to do this over a longer period.

    This is where I am at at the moment.

    travelled 2985km used 118.5 litres in doing so.

    = 118.5 divided by 29.85 hundreds of km = 3.96L per 100km
    mpg = 282 divided by 3.96 = 71.21 mpg

    as these results were taken over a long time the possible up to 1 litre filling up error between start and finish re fills is all but eliminated.

    Note: I ride my zzr mostly on highways at 90km/h as only learner licenced (yes 80 is the max for learner down here but the extra 10k's stops cages most of the time pulling stupid over take monouvers etc in 100km zones, but thats another story).

    Also don't thrash it (as a new clutch is not far away) although have pushed to 13000revs a couple of times.

    lots of LUV v8.
  7. Re: Fuel consumption calculations

    Why express fuel consumption in "litre per 100km" when kilometre per litre is a lot easier to understand.

    All you have to do is calculate your milage between petrol stops divide it by the number of litres to fill the tank up. Presto: km/litre.
  8. My bike consumes about 6-7.5 L/ 100km (I have a fuel consumption readout on the dash that tells me what my L per 100km is :) )

    It can go up to 15-25L/100km when you really push it.
  9. Very good fuel consumption figures there! The ZZR is a frugal one though, even when thrashed, as I'm sure you'll find. ;)

    My fuel consumption is around 6.5L/100km, give or take. How I ride does have some effect on usage, but usually it's not really noticeable over a full tank (that includes highways).
  10. Re: Fuel consumption calculations

    Convention? Standard? Easy to compare?
  11. Re: Fuel consumption calculations

    'Cos, rightly or wrongly, the std way to express fuel consumption in the metric edition, is "litres per 100 km"

    Doesn't really matter how you say it, as long as we all say it the same, so easy comparisons are done.

    The cat usually gets 5 litres per 100km.

    Recently tuned the beast (still need to do a carbie balance, but that'll happen when the valves get done, in couple of thousand K's time.) & have been getting 4.51l / 100k's, I'm happy with that, esp seeing its got a "go fast" ignition module, and a "go fast" Yoshi can.

    nearly 400 k's to the 18 litre tank :cool:
  12. Re: Fuel consumption calculations

    you have sort of missed the point a bit......after 2 tank fills 4.39L/100km was the fuel consumption. After now 11 tank fills it stands at 3.96/100km. this figure is more accurate. As I was trying to explain that if you miss fill 1 of your fill ups by 1 litre(which is not that hard to do if you go to a different servo that the driveway leans at a different angle or is on a slope etc) it stuffs up your results hugely over 1 or 2 tanks but is virtually out of the equasion after 11 refills or 1/11 of the effect on the results. example apparently the tank in my zzr is 16 litres if it can all be used (not likely) b4 conking out at 4.39l/100km i'd expect 364kms range to dead empty.

    at the more accurate "average" figure of 3.96L id get 404km.

    but yes you are right as a ballpark figure you could do it tank by tank.

    Still craps all over my cage ute at 11.7l/100km
  13. Great tip, Bob. I'll be doing this as soon as I get my bike. I had planned on resetting the trip meter just riding till empty then fill. but your way makes more sense.

    Quetsion: How long does the petrol last in the reserve tank? I mean the life span if there is such a thing.
    I read somewhere that bikes in storage should have the tank drained, what if I never switch to reserve?
    Does this mean the reserve petrol is stored in there forever?

    Yes I'm a noob :D
  14. as mentioned at last weekends spanner danner, BHHs ROCK

    Bobs Handy Hints :)
  15. im.on.it

    the reserve is not actually another tank. Its just the fuel is being "sucked up" from lower in the tank.

    Think of it as 2 different straws sucking up the fuel. THe normal one does the work most of the time but when you switch it to reserve, the lower straw is used and it can access that last little bit of fuel.
  16. Thanks. I was wondering that. I just bought a bike and was wondering.
  17. i have no guage or odo, so i have to wait till i hit reserve. but i have a fairly good odometer in my head hehe.
  18. Even if you have a "reserve" tap, it's not always good to rely on it,
    cos where does all the shyte, banana leaves, water and misc crap go to in a fuel tank?? the bottom, where does the "reserve" suck the fuel from? The bottom!! yucky fuel!
    IMO, reserve is for emergency use only.

    My bike doesn't have a reserve, nor did the last one. In fact you can't get to the fuel tap on the Cat, it's only there to stop the fuel flow when you remove the tank. The Cat is a carbie beast, but most fuel injected bikes are the same.

    Use the odometer, keep an idea of what you used each fill and how far you got. Over time you'll get to know the beast and can predict with surprising accuracy when you'll need a fill up, depending on what sort of riding you're doing. The more often you do it, the more accurate it becomes.

    Me, I fill up at around 250 k's (a weeks worth of work 'n back) takes around 10-11 litres, tank is 18 litres. S'posed to have 5 litres "reserve" once the light comes on, but the light don't work :? , and I can't be bothered ripping the dash apart to find out why, I use the trip meter, far more accurate.

  19. The other theory Iffracem, is to keep running into reserve so the crap doesn't build up to a dangerous level. ;)
  20. Yeah... but I'm an ofarc.. so I'd forget to switch it back off reserve ](*,)
    Then I'd be knackered!