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  1. #11
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    The technology hasn't been mass manufactured because of costs. It is expensive, and does add some weight also I'd guess up to 10 lbs or more for all the sensors and devices to run a fuel injection system, with up to 5 more pounds for a direct injection system. All the pumps, hoses, sensors, and wires are heavy, especially when it is only on a single cylinder engine, not spread out along multiple cylinders. Hence, Canondale's extra weight.

    My 1985 Yamaha RZ350 uses a Banshee engine, but has servo controlled exhaust valves in different cylinders. It also came with catalytic convertors to pass emissions for street bikes at the time.

    Direct injection technology is coming from a company called Orbital . It seems all the companies are contacting them for development help.







  2. #12
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    I think that one of the reasons you won't see much of the streetbike tech stuff on true race caliber dirt pounding bikes is that it requires a steady, spike free power system, thus a battery as a ballast which means charging coils and circuits. Technoligy will probably catch up to the weight, heat, and vibration problems soon, so who knows.




  3. #13
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    direct injection

    There are other alternatives to the Orbital direct injection system, previously mentioned. Rev! is proceeding with the Ram Injection system developed at OMC / Bombardier. It has some advantages over the Orbital system. There are other systems that merely use a high pressure pump and injector (similar to a diesel system) that have merit.

    A decent electrical system will use good regulation components and properly sized capacitors to control ripple.




  4. #14
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    He, he, here's another one for you:

    I just picked up a 1985 Suzuki RGV 250 Gamma Walter Wolf edition that also has selenoid operated powervalves. Geez, I didnt realize they had this stuff around for this long...

    On a side note, I picked the bike up for free, and it even runs!




  5. #15
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    Do all these high tech road bikes and snow mobiles require the amount of engine maintnance (top ends) that dirt bikes do? Are their riders, as a group, as inclined to work on their equipment as dirt bikers are? Perhaps one of the reasons dirt bikes aren't more electronic is the makers fear of providing a product that people feel they could no longer work on. Possible?




  6. #16
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    There should be no fear on working on products that contain sensors and electronics. It just requires that the OEM supply, or have available, the proper diagnostic equipment for a reasonable price. It's a new set of tools.




  7. #17
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    Someday, you make a really good point. I know that my buddies new Prairie650 fourwheeler is all electronical and stuff, and although he has so much more experience with engines and the like than I do, even he wont work on his fourwheeler. I can definitely say that if they move more towards electronics that I would probably be sticking with my '99 KTM 300 for quite a while, just becuase I wouldn't wanna take my bike to a mechanic to have it worked on.

    KaTMandoo




  8. #18
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    Zackly!




  9. #19
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    FI--what's the point?

    I mean, what's the point in a 2 stroke? That's not an actual question, but rhetorical, unless somebody can come up with a convincing answer. Where does fuel go in a 2 stroke? CRANKCASE What mechanism "pushes" fuel during intake cycle on a 2 stroke? PISTON What determines volumetric efficiency of a motor? HOW MUCH AIR AND FUEL CAN BE SHOVED INTO THE COMBUSTION CHAMBER BEFORE FIRING What typically provides impedance of this process in a 2 stroke? EXHAUST

    Obviously, an electronic powervalve would be much more likely to result in improved efficiency than fuel injection in a 2 stroke, unless we're talking about a "supplemental" injection during the late intake cycle directly into the chamber?

    I'm not tryiing to be a smartass or knowitall, it just seems that fuel injection is being thrown around here like it is really an advance in 2 stroke technology. Also, I am solely here to learn, not teach. And if anyone can provide an answer that would provide me entirely wrong, I'd be happy as a clown!!

    While we're on the topic, 2:1 cc 4 stroke: 2 stroke allowances are unfair in the AMA. Volumetric efficiency of 2 strokes suck because of the amount of exhaust still present in the combustion chamber during firing. I think the VE of a typical 2 stroke dirtbike motor is around 60%. The 4 strokes are achieving about 90-95% VE.

    The rule should allow for this. ie, a typical 250 4 stroke should have to compete against a 160-170cc 2 stroke. Sorry 4 stroke folks, that's just the way it is.

    I'm sure none of the above is new...:think




  10. #20
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    You are glossing over the rather complex relationship between fuel curves and how they are related to pressure. A conventional carburator is nothing but a series of passages that react to pressure differentials between the engine and the atmosphere. Your average carb's inability to adequately adapt to the changes in atmosphereic conditions and the resulting changes in carb metering as well as volumetric density leaves huge room for improvement.
    Without going into a disseration level explanation suffice it to say that while standard slide needle carbs have served our purposes quite well up till this point they are remakably crude and pale in comparison to what is possible with closed or open loop feedback EFI systems. There is no question that there is a cost and complexity associated with moving forward, but as Charles Kettering so eloquently put it "the price of progress is trouble"

    As far as displacement factors go, if you do a stroke averaged analysis of BMEP you'll find your math is off.



    m y   s i g n a t u r e:


    "another beautiful theory beaten to death by a gang of ruthless facts..."

    - Tom Hanna (Master Metalshaper/Nitrogeezer)

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