Longevity, FI or Carbs?

Discussion in 'The Perfect Line and Other Riding Myths' started by LPRoad, Nov 27, 2013.

  1. SteelJM1

    SteelJM1 Undercover KTM rider

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    No I was just responding to concours listing every single part of a FI system that can go wrong, while only talking of a carb as if its a single entitity. And sprinkled with some snarkyness too. Because I can just as easily list

    Float needle
    Float needle seat
    Floats
    Float hinge
    Pilot Jet
    Main jet
    Emulisifer tube
    Slide
    Needle
    Diaphragm
    coasting enriching circuit
    Accelerator pump
    All the gaskets

    And so on. Those claiming that carb's are less complex than FI are barking up the wrong tree. They are complicated mechanical devices, wonders of engineering but have their shortfalls too.

    Agreeing that both can have parts that break, the FI has the advantages of adjusting itself automatically to the conditions. Makes for a cleaner and more efficient burn.
    #61
  2. ttpete

    ttpete Rectum Non Bustibus

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    The biggest reason for EFI is that carburetors can't meter fuel precisely enough to pass emission standards. The companies tried to make closed loop systems using carbs but failed.

    I was involved with vehicle emissions testing at Ford from 1968 to 1980, and we struggled to meet the standards using carburetors with all kinds of modifications and devices. We did things with cam profiles and timing, and also worked with ignition advance curves. Fuel systems engineers had carburetors flowed and tested by the hundreds and changed them out daily. Every test vehicle had a trunk full of carbs. Those of us who lived in the 1970s and drove the vehicles know how horribly bad they ran and performed. I'm glad to see carbureted vehicles gone.
    #62
  3. ohgood

    ohgood Long timer

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    one carb on the shelf costs $300 or so. one complete fuel injection system on the shelf costs....

    yes I know that was unreasonably unfair.

    if the klr guys ever spring for efi because it's that much awesomerrrr wake me up.
    #63
  4. SteelJM1

    SteelJM1 Undercover KTM rider

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    Haha, cant really add klr owners to the mix, theyre a different breed.

    But i have seen FI DR mods.

    If there was an aftermarket FI system available for purchase for a reasonable price for my DR, id jump. Better than any pumper carb.

    Sent from my Tandy 1000 mobile using DOS
    #64
  5. Tripped1

    Tripped1 Likely Lost.

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    Also you tune it with a laptop and a plug under the seat, instead of burning the shit out of yourself for hours at a time trying to get the needle height, floats, jets, idle adjustments just so. :lol3


    I don't miss carbs at all, and despite having only fuel injected bikes for the last 15 years I have replaced nothing more complicated than dry rotted vacuum lines for the idle stepper on my Speed Triple. Now the bike didn't have any issues, but you could see daylight through one of the lines. I only found it because I was wondering where the sucking sound was coming from.
    #65
  6. Pecha72

    Pecha72 Long timer

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    15 year on carb´d bikes, now 7 years on FI bikes... I´m not going back. I don´t really have that much AGAINST carbs, they were okay, but FI works better just about everywhere (esp. high altitude), is more easily adjustable, and gets better throttle response and mpg.

    Longevity - which fuel system type has been used in practically all cars all over the planet for the last 20 years? Seems to work pretty well on four-wheelers, too.
    #66
  7. farqhuar

    farqhuar Lone Wolf

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    Another rider with more than 40 years of riding experience saying +1 for EFI - best thing that has happened to bikes in my lifetime. :clap
    #67
  8. henshao

    henshao Bained

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    I would take a SINGLE carb over EFI, but EFI over multiple carbs.
    #68
  9. Garp

    Garp Long timer

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    I'd probably agree. Most of my FI experience has been on multi-cylinder bikes, and they have been largely flawless. The FI on my KTM690 was a moody SOB, prone to random stalling, hard starts etc, regardless of the map installed.
    #69
  10. Paebr332

    Paebr332 Good news everyone!

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    I am getting close to completing the rebuild of my 1988 Hawk GT. I am searching high and low for an easy way to get rid of the carbs and fit an EFI system. Down to researching building my own based on an Arduino controller. Having a brother who used to design fuel injection systems could prove useful. I just want the bike to start in any temperature and run well at any altitude/temperature and self-adjust for winter/summer fuel blends, etc. Carbs can't do that.

    Replacement diaphragms will be the unicorn horn for a 20 year old carbed bike. Of course by then some enterprisiing person probably will be 3D printing them on demand.
    #70
  11. Garp

    Garp Long timer

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    That sounds like a hell of a lot of work, to avoid a little bit of work. Just my opinion and worth what you paid for it :D
    #71
  12. Norduro

    Norduro Thumping

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    Owning a 2001 BMW F650GS with FI (probably one of the first bikes that had FI?) I have made different experiences. The FI works flawlessly on my thumper and it is twelve years old now - never needed any cleaning, adjustment or maintenance at all.

    Effortless cold starts, barely any power loss in high altitudes, no worries about getting it running again after it was standing for some time, *great* fuel economy, and so forth. I would not want to go back to carbs, even on a thumper. :clap

    The fact that cars have been running on FI systems for decades certainly contributes a lot to the fact that FI systems are as reliable as they are nowadays. A modern FI system is just something you do not have to worry about at all.
    #72
  13. SteelJM1

    SteelJM1 Undercover KTM rider

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    I would say that that has much more to do with katoom than the basic principle of FI. Which is why i would hope they license 2 smoke FI from Polaris instead of trying it themselves and invariably fucking it up.

    Sent from my Tandy 1000 mobile using DOS
    #73
  14. Tuna Helper

    Tuna Helper Rawrr!

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    I have. Buying a used bike that "ran when parked" only to find the slides, jets and tubes gummed up.

    My CB750 could probably use a bit of carb tuning, but I don't ride it enough and it runs well enough, so why bother.
    #74
  15. slartidbartfast

    slartidbartfast Love those blue pipes

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    I have two ~ 20-year-old bikes with FI and the fueling system still works like a champ!

    I have owned a couple of 20-year old bikes with carbs (my airhead was ~20 when I got it) and while neither has been terribly difficult to fix, thay have had issues, such as rotted diaphragms and plugged idle jets. That said, replacing the fuel filter on the injected GS was a bit of a pain, and one of the throttle bodies is getting pretty worn.

    On balance I'd say it's about even - but I'd still go for FI on any new bike today, regardless how long I was planning to keep it.
    #75
  16. buls4evr

    buls4evr No Marks....

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    The really good news is that KTM uses a Keihin FI system on their bikes (like my EXC500), so it is just like all the other bikes from Japan using Keihin. They all learn and adjust as they go.Sometimes there is no reason to reinvent components when you can just buy great ones..... KTM gets this. Brembo, Renthal, EXCEL, WP, Polisport, Magura hydro clutches....
    #76
  17. Reduxalicious

    Reduxalicious Been here awhile

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    Having used my KZ for transportation to work, every day for 8 months a few years ago.. EFI was VERY WELCOMED when I finally got a newer bike. Carb'd biked do not like to start when it's below 55 :rofl
    #77
  18. BuddingGeezer

    BuddingGeezer Been here awhile

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    My 1991 Honda ST1100 started fine at 14 degrees F. Haven't tried it any colder than that.
    #78
  19. concours

    concours WFO for 41 years

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    I always rode my XS1100 well into the 20's, never any issues. You bring a up good point. Most FI systems stop fueling when voltage drops to 9V or so, when cranking a cold engine, the starter drawing a shit ton, it can mean a no start. Not usually an issue with bikes, but if cold weather storage/riding are planned, it can be something to consider.
    #79
  20. davidji

    davidji bike curious

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    Modern EFI bikes are certainly simpler to operate, especially on cold mornings.

    OTOH bump-starting a modern EFI bike may be a non-starter when the battery is dead. Depending on the bike and how dead the battery is.

    Some carb'd bikes run fine with no battery at all. I don't know of EFI bikes that will, but I can't swear there aren't any. Are there any kick-start EFI bikes?
    #80