Exhaust Length and effects on engine ...
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  1. #1
    Registered User Array LimitedEdition's Avatar
    Join Date
    Feb 2002
    Japanese Twin

    Exhaust Length and effects on engine ...

    Okay Hindle Pipes for the RC51 come in 16", 18" and 20" lengths. They recommend 20" length for the RC51. What effect would a shorter length can have on Torque? HP?

    Why 20" recommendation? To adhere to noise regulations?

    Please tell me anything you know .. I just want pipes .. and I don't know anything about how a bike works !!

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  3. #2
    Registered User Array Jumby's Avatar
    Join Date
    May 2002
    North Van
    Zx6 07, Crf 450r, Yz250f
    Pipes are put on to help ur bike breath, they do this by helping the motor to increase the negative pressure pulse behind every power stroke, this lets more fuel and air charge fill the cylinder. When u increase the amount of mixture u increase the torque and hp, but only if u a just the fuel mixture. If more performance is what ur after then go with the shorter lenth, but remember u don't get nothing for free by doing this u will take away from ur bottem end power making the bike more peeky. They recomend the 20" so the bike is more streetable, but the choise is urs.U should realy go and do a Dyno run first and see what ur bike does stock, while u doing that but it on a EGA (Exahst gas analyser) to see if the bike is running rich or lean. Then through on the pipes u want and see what happens next, chanses are u bike will be running very lean, to adjust this u might need a power commander to change ur fuel injecter mapping. It sounds like alot of work but it aint. There is a shop called Futur Cycle in Richmond its a Harley shop but I take all of my Race bikes there to test on his dyno Its the best in town, and the guy who runs it is VERY smart (Bill). I hope I helped.

  4. #3
    Moderator Array TeeTee's Avatar
    Join Date
    Feb 2002
    Out to pasture in the 'Wack
    04 Kawi Z1000,
    Are all 3 of those sizes for the 51 only? If so then they are tuned much as Jumby says to suit your riding style. The longer ones will work better at lower rpms and the shortest better at higher rpms. And the middle one, strangely enough, best at the middle rpms.

    Be honest with yourself if you get one of these. The shortest one will probably not feel as good as the longer ones unless you're racing or a serious canyon carver that always keeps his engine on the boil and is willing to live with some low rpm stutters, power gaps or whatever. The longer one will probably be best for the real world where you pull out from behind Pa Kettle and grab a handful without downshifting enough and want the good solid torque to roll on.

    Or at least that's the theory. For all I know they have the long one so your GF on the back doesn't melt her high heels on the can....
    A backyard mechanic without a service manual is just like a hooker without a lamp pole.... they are both in the dark.

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