EFI versus Carb.
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Thread: EFI versus Carb.

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    EFI versus Carb.

    The Benelli Imperiale seems to be getting a reputation for jerking on and off the throttle.
    Also the idling revs are set electronically at 1500, which I find a bit too fast. Using the idle adjuster is ineffective.
    I´m wondering if it would be feasible to fit a carburettor instead, to put the control back into my hands and get a smoother ride.
    I could easily fabricate an inlet tract to suit, but what I don´t know is if all the electronics are related to the fuel supply, or if their influence extends further, and if so what the effects would be.
    Any ideas welcome.

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    Senior Member Engenia's Avatar
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    Damn noisy horseless carriages!

    Modern engines are only as powerful, economical and tractable as they generally are because of EFI. Sure you could fit a carby in place of the EFI system, but that would be a backward step IMHO. Better to fix the problems you have, rather than replacing them with a whole new set. Get yourself the equipment necessary to work with what you have and study up on how to use it. It's daunting, but not insurmountable, and very satisfying when you conquer it.
    hooroo, Errol www.engenia.com.au [139,200 km - and counting .....]

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    GBo
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    Quote Originally Posted by Engenia View Post
    conquer it.
    I love your optimism

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    I see where you´re coming from Engenia, and I´m still at the ¨wondering ¨ stage, however there are some good reasons for considering a carburettor.
    It seems that the Imperiale has a general problem with a sudden surge when the throttle is opened, and another when it is closed. On a wet road it could be sufficient to initiate a slide. The idle speed being set electronically at 1500rpm is far to fast and cannot be altered by the inoperative adjuster, which indicates to me that they could not get the engine to run any slower on EFI.
    The complex electronics (on a retro machine ) look to me like an unnecessary effort to give the dealer more power over your bike and your money. I understand that the correct lead to control the ECU is not available, and if it were, my MacBookAir would be a bulky item in my toolkit compared to a small screwdriver.
    If I want to ride fast I use my Moto Guzzi, with the Imperiale I want smoothness and tractability, and I´ve always been able to accomplish that with carbs on a wide variety of machines, so if the manufacturers can´t get the bike to run properly with EFI then I think your confidence in my ability to do so is seriously misplaced.
    What I need to know is if the ECU is restricted to the fuel system, or if it controls other aspects of the engine´s operation. For example, if it controlled the timing as well, could I substitute electronic ignition ?

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    GBo
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    It will control the ignition. But you could leave all that intact. The question is will it throw an error if you unplug the injectors(but again worst case leave them/it plugged in Or throw an error if the lambda goes way off.

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    I'm an old fart. Been riding bikes for over 50 years and have a lot of experience with carby tuning. Not so much with EFI. So I can see where you're coming from Mr Monoped.

    If you're serious about the change, I'd suggest you'll need something around 39-40mm. Keihin or Mikuni seem to be more reliable and better at metering fuel than most other brands.

    As for the ECU and the multitude of errors it'll spit out if you disconnect the throttle bodies, perhaps you could get rid of it entirely. Once you've got rid of the throttle bodies, all you need from the ECU is a signal to make sparks at the plug. Any aftermarket ignition system will do that. My favourite is Ignitech. They make a quite sophisticated and versatile electronic ignition unit that's very competitively priced. Dunno whether it'll work with the existing crank sensor though. But if it doesn't, it's not an insurmountable problem.

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    I´m pleased to hear that my idea does not sound completely impossible on first glance, I would prefer to ditch the ECU completely so that the timing was under my control as well. Of course the guys at the MOT centre might have something to say (if they noticed). Mikuni would indeed be my first choice, tuned for best power at low speeds, to suit the terrain here.
    Having removed the slack from the cable I shall see if it helps to control the throttle to minimise the jerking, a good excuse for a ride to Órgiva and back.

    My handle should probably be explained -- having spent many years studying metaphysics I can only claim to have one foot on this planet, the other flails wildly in a non-physical environment. This means that I have many silly ideas which frighten the horses to the extent of persuading me to keep as schtum as possible on the subject.

    Before doing anything to the bike I need to understand exactly how it works, and looking for engine diagrams etc., I´ve so far drawn a blank.
    Any suggestions as to where to look would be delightful.

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    Senior Member DenH's Avatar
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    Quote Originally Posted by Onefoot View Post
    I´m pleased to hear that my idea does not sound completely impossible on first glance, I would prefer to ditch the ECU completely so that the timing was under my control as well. Of course the guys at the MOT centre might have something to say (if they noticed). Mikuni would indeed be my first choice, tuned for best power at low speeds, to suit the terrain here.
    Having removed the slack from the cable I shall see if it helps to control the throttle to minimise the jerking, a good excuse for a ride to ”rgiva and back.

    My handle should probably be explained -- having spent many years studying metaphysics I can only claim to have one foot on this planet, the other flails wildly in a non-physical environment. This means that I have many silly ideas which frighten the horses to the extent of persuading me to keep as schtum as possible on the subject.

    Before doing anything to the bike I need to understand exactly how it works, and looking for engine diagrams etc., I´ve so far drawn a blank.
    Any suggestions as to where to look would be delightful.
    . Would the bike pass the emissions with carbs ?one of the other reasons they use efi is to pass increasingly stringent standards.
    when i was young i was very indecisive,now im older im not so sure.

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    emission tests ?

    In all my years of biking, I have never had a bike emission tested at an MOT, They never check the beam aim, not even if it is high/ low , or of sufficient brightness.
    Never done one abroad so can not comment on that.

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    Things are fairly stringent here Freeatlast, though when I had the Guzzi tested after getting a Spanish identity for it, I had to hand the tester a screwdriver so he could adjust the beam. He failed me because the rear tyre (with which it came new) was too thin for Spanish taste.
    Good point DenH, I doubt whether they are sufficiently au-fait with Chinese/ Indian/Italian bikes to know whether they should have a carb or EFI, but plenty of bikes with carbs can be seen here, so if I got it right I might get away with it with a very lean mixture on tickover.
    It might be wise to wait a little and see if any modifications come onto the market to ameliorate the problem. They need to find a way of bringing the idling rpm down, since there would not be such a jerk if you were opening up from 900 rpm rather than a busy 1,500. Benelli will be crucially aware of how the bike stands up against the Enfield in India, and a slow, steady tick-over is a box they have yet to tick.
    Having removed the slack from the throttle cable, I´m finding the jerkiness a bit easier to control, and it might be that I adapt to the bike as time goes on.
    Certainly the main impression is that of a solid, practical and very useable motorcycle which is a delight to ride.
    The Enfield is toast.

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