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Any ideas why your bike would suddenly start munching 25-30% more petrol

Discussion in 'Mechanical' started by R1 Chickie, Feb 29, 2012.

  1. R1 Chickie

    R1 Chickie Guest

    I used to only have to fill up my bike every 4 days, now its every 3 day, this only started happening in the last couple of weeks. Same route, cant say Ive changed my riding style, checked the obvious like tyre pressure. Any sensible answers to this please??? (Can we please keep the willy waving, sarcasm, pedancy to a minimum and give me some real options to investigate)
     
  2. Ducky

    Ducky Quackers! +

    Messages:
    1,351
    Slow buildup of crap in the air filter...perhaps something is blocking it so it's starting to run rich? Dyno session would be good to check the state of tune. :thumbsup:
     
    Dhan Rollioni likes this.
  3. GuzziRob

    GuzziRob Race Rep +

    Messages:
    896
    The obvious would be a petrol leak, but you would smell it.
    Does the engine sound or run differently?
    Is it still producing the same power?
    Pull a plug out and look at the colour around the electrode to see if the engine is running rich.
     
  4. Skortchio

    Skortchio Caustic +

    Messages:
    2,035
    The ECU should be able to compensate for small changes in the air / fuel ratio, if it's using a noticible amount of fuel then as already said the amount of fuel being supplied has either increased for some reason or it's going somewhere it shouldn't.

    First step would be to confirm it's not going somewhere other than into the throttle bodies, as it's an electronic pump on an FI it might only present while riding so the smell may have gone by the time you come to a stop, especially if you park in a garage / car park where you'll be moving at slow speed for the last minute or two of your trip.

    Assuming there's no physical leak, then something is causing your bike to think it needs more fuel. Has the bike been on it's side recently?
    A common cause of problems like this is the TPS (throttle posisiton sensor) getting thrown out of whack, usually by the bike hitting the deck and cutting out while revving, or possibly an extended period of dead battery causing the ECU to lose it's zero point.
    A quick check on the R1 forums will give you a 'how to' of resetting it, usually involving leaving the bike running on idle for a period or a combination of ket turns etc.

    If the bike is sluggish at low speed / revs then it would indicate it's over fuelling.

    After that's off the list you're onto physical changes, external to the engine is the obvious - higher flow air filter or exhaust, injector remap or power commander.
     
    Dhan Rollioni likes this.
  5. r1jay

    r1jay Race Rep +

    Messages:
    316
    Depending upon which model it is i would be inclined to get the exup valve looked at. if it is starting to stick then this will give the ecu different readings. this happened on my 2007 r1 and then i noticed that the cables on the exup had snapped so it wasnt working at all.
     
    Dhan Rollioni likes this.
  6. Les

    Les British Superbike +

    Messages:
    2,559
    Has anyone done anything lately to it? I think you said it was in a workshop somewhere recently. We replaced the Exup valve motor on Jordan's carb'b R1 & it was straightforward but that fault was confirmed by the tacho needle which used to double as a fault indicator, at least on early models. It had been seized since he got it & could be your problem. As others have said, a Dyno run will certainly find it & may show up other easily sorted 'tuneable' faults. There's a good (reputable) place I use in Edenbridge called HM racing 01732 869920, if you can't find something local, takes about 2 hrs total.
     
  7. HAYABUSADAVE

    HAYABUSADAVE Custom cruiser +

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    1,068
    Was going to suggest when was the last time you replaced/cleaned your air filter, and plugs......:thumbsup:

    Haven't laid the bike up without additive in the tank have you and now have some injector gumming??????
    Just a thought, these things happen with shitty unleaded....I know some that have been caught out......

    Are yur coils ok?? ( no, not those types, the bike ones...) I say this as my Busa drank a tank full of juice once just to go to Box Hill, altho' yours isn't so thirsty by the sounds of things, It also misfired at low revs, this was down to a cracked coil, ( cause, shit house bike dealer) replaced it and bingo! back to normal....Just another thought.....:thumbsup:
     
  8. Skortchio

    Skortchio Caustic +

    Messages:
    2,035
    A dyno run won't find it, it will only show if the air:fuel is out and/or if the bike is under performing - but without a previous run that's not to say the power has actually dropped.

    It's important not to confuse havy fueling / poor performance with increased fuel usage.
    Reducing the air intake will cause overfueling, but not actually increase the amount of fuel used.

    If the bike has suddenly started doing it, then it's a change that's at cause not something long standing. Simple question is "What has changed recently?"
     
  9. ramrider

    ramrider Race Rep +

    Messages:
    773
    After that's off the list you're onto physical changes,[/quote] are you saying she has put on weight
     
    kitten_art and HAYABUSADAVE like this.
  10. HAYABUSADAVE

    HAYABUSADAVE Custom cruiser +

    Messages:
    1,068
    are you saying she has put on weight[/quote]

    I spose pregnancy can be a biker womans trait......you know, the power to weight ratio bit......:eek:
    A dyno won't help that.....but a coat hanger can......:puke:
     
    R1 Chickie likes this.
  11. Les

    Les British Superbike +

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    2,559
    Now the serious stuff is out the way...can we please get back to taking the piss?;)
     
    HAYABUSADAVE and kitten_art like this.
  12. Skortchio

    Skortchio Caustic +

    Messages:
    2,035
    are you saying she has put on weight[/quote]

    More rider weight would need more throttle to maintain the same rate of acceleration, which would need more fuel... :whistle:
     
    HAYABUSADAVE likes this.
  13. JimG

    JimG British Superbike +

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    1,064
    A thought was - are you filling up sooner because of a dodgy fuel gauge, and not noticing you are putting less fuel in due the constant price rises (£21 six months ago, £20 today but a couple of litres less)? However, I'm not sure an R1 has a fuel gauge?
     
    Skortchio likes this.
  14. R1 Chickie

    R1 Chickie Guest

    Its been recently serviced, not recently dropped, no petrol leaking and its not under performing so it sounds like the EXUP valve!

    No JimG, I am putting in 20 quid every time, I run to the last drop :)
     
  15. Skortchio

    Skortchio Caustic +

    Messages:
    2,035
    EXUP would make sense if you spend a lot of the trip at low to zero rpm, in traffic. Quite likely in London I'd imagine.
    Easy to get it checked out though, worth resetting the TPS while you're at it.
     
  16. Les

    Les British Superbike +

    Messages:
    2,559
    Tanya...at low revs?? Has she really calmed down that much?
     
    _Yappa_ and HAYABUSADAVE like this.
  17. R1 Chickie

    R1 Chickie Guest

    Actually, it is massively underperforming, I was battling to race a 650 today, she has the power of a 600 not a 1K! My poor baby, whats wrong with her :-(
     
  18. Skortchio

    Skortchio Caustic +

    Messages:
    2,035
    Sounds a lot like the prognosis is unchanged, siezed EXUP would cause power problems as would the ECU all confused. The battery being dead a while ago could of contributed to that, if the problem manifest afterwards?

    Gabby needs some TLC, a good checking over of the working parts (takes time but not swanky equipment), then assuming all is well a dyno and ECU reset might be on the cards.
    FI fueling is a great invention, just a PITA when it has problems.
     
  19. Skortchio

    Skortchio Caustic +

    Messages:
    2,035
    Slight ammendum, what were you racing and at what speed?
    Under about 80 you're unlikely to really gain on a modern 6 if they're giving it large.

    Make sure there's no obvious fault, EXUP, cat in the air filter, vole in the exhaust, spark plug missing, etc.
    Then put it on a dyno and find out what the engine is putting out.

    You say you aren't riding differently but is the bike revving higher? I'm talking worst possible case scenario here bit there's a reason you could be burning more fuel for same speed and getting less go. But you probably don't want to hear it, its highly unlikely anyway.
     
  20. HAYABUSADAVE

    HAYABUSADAVE Custom cruiser +

    Messages:
    1,068
    Maybe, just maybe, the 600 chappie was a better rider????? Shit happens..... :confused:
     

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