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Can someone please explain.....

Discussion in 'General Motorcycling Discussion' started by doonx, May 26, 2005.

  1. What "short shifting" is and what is it's advantage ?
    When is it best used ?

    sorry to sound dopey, I've heard the term but outside guessing that is a series of rapid gear changes I don't know what it is.
  2. From my limited understanding of the process it is when rather than revving the bike towards its redline you change gear earlier and use the torque to achieve forward motion.
    I tend to short shift the Duke more because of the torque available to me to do so.
  3. its when you shift up before you get the full power out of the gear. mainly used on powerful bikes to stop the wheel from lifting i spose. plenty of reasons to do it, i dont really think about it when i do it tho....
  4. For instance, in the twisties, if you come out of a tight corner, and are about to accelerate through a long opening curve, it can be better to 'short shift' into a higher gear before entering the faster corner so that you don't need to change gears halfway round.

    Also, on a twin with lots of torque, it just feels good. ;-)
  5. so it's not something that really comes into play too much with a 250 as it hasn't got the torque to make it really worthwhile ?
  6. I could be very wrong, but I do it any way. Doesn't short shifting save on fuel? Like when you're low on fuel and you're not sure how far the next servo is, you start short shifting to get into 3rd or 4th (whatever you cruise in) quickly to conserve fuel... Someone cut me down...

    Anyhoo, while we're asking stoopid questions, can someone please explain "running lean" and "running rich" for me....

  7. Running lean means there isn't quite enough fuel reaching the engine. Running rich means there is a little too much fuel reaching the engine.

    Edit: Well...it's more a more or less fuel then an imaginary optimum. Running a bit rich can sometimes be a good thing for example.
  8. Running lean == 'a higher air to petrol ratio then desired for optimum performance and efficiency' -> can lead to seizure

    Running rich == the opposite (and won't cause a seizure)

  9. So what are the symptoms? When is it a bad thing? What can I do about it?

    PS Sorry Doonks, didn't mean to hijack your thread... :D
  10. running at lower rpms does conserve fuel... i do it as my bike behaves better at lower rpms.

    I shift at the redline/shift light when I am pretending to be valentino rossi, or I want to make small children cry and block their ears :LOL:
  11. yep, it'll help with fuel consumption, lower revs means less fuel used. running lean means more air in the fuel air mix than there is supposed to be and running rich means too much fuel in the mix. either can cause problems if left unfixed....

    and yes, it is still useful on a 250. like moike said, better to be in a taller gear going around a fast corner than to change halfway through.

    you do it without even realizing it most of the time, its just when trying to squeeze every inch of performance out of your bike that you start to really think about it....
  12. Running too lean can cause pinging I think which would damages the engine.

    Running rich dumps unburnt (and therefore wasted) fuel out the exhaust pipe.
  13. damn, some faster typers than me :LOL:

    lean you will tend to over heat and revs will be higher with less power. between the heat and the lack of lube, can do some REAL damage to the motor.

    rich you'll tend to get a bit stuttery and you'll have this loverly black smoke coming out the zorst when you rev it. this will foul plugs and generally cause your bike to run like a pig, too much excess carbon cant be a biatch to clean up to get things hunky dory again :?
  14. oh man ...................... :cry:
  15. Compressing air heats it up (which is why CO2 fire extinguishers get very cold, as the compressed gas cools as it is released).
    In a lean engine, the air in the cylinder can get too hot in the compression stage, self-igniting the air/fuel mixture in a diesel-esque kind of way before your spark plugs get a chance to, well er ... spark and more importantly before the piston has reached it's optimum position past TDC.

    You get a similar effect if you let the engine overheat too far. Sounds like you've got a bag of nails in your engine. Not a healthy sign.