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Stock Porting questions

Discussion in 'XJ Modifications' started by cruzerjd, Oct 28, 2007.

  1. cruzerjd

    cruzerjd Member

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    Just got curious about this and thought I would ask. When I removed my intakes on my 1982 Seca 650, I noticed that the intake ports were smoothed and painted with black paint, there also had been some machining work on #1 and #2 cylinder intakes to match the intake to the port. Just wondering if this is normal or if someone may have been trying to port and polish the head for a bit more power. I know my Seca does pull harder than my friends Maxim 650 especially above 6000 rpm's. Haven't bothered to pull the valve cover to look for cam changes or anything, just curious about the ports. I could i guess get pics the next time i pull the carbs, but crossing my fingers that I won't have too for a while, cruzerjd
     
    cruzerjd, Oct 28, 2007
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  2. worldsfastestxj550

    worldsfastestxj550 New Member

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    secas have bigger cams
     
    worldsfastestxj550, Nov 13, 2007
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  3. shamus

    shamus Member

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    I noticed on mine that it looks like someone has attacked the inlet with a dremel. I'll get a photo if I take the carbs off again
     
    shamus, Dec 12, 2007
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  4. desmotom

    desmotom Active Member

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    I ported my heads and the top end was better until my jets couldn't keep the toilet flushing, need bigger jets.......next season
     
    desmotom, Dec 14, 2007
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  5. RickCoMatic

    RickCoMatic Well-Known Member

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    The intake and Exhaust Ports are Factory "Ported". That is to say ... machined to remove any casting imperfections. I was once told by a Yamaha Schooled Tech ... that the Porting was done by and automated machine that brought the Porting tolerances very close to Maximum relief of material.

    All you should have to do for a very slight improvement in performance is Polish and ... (remove, by hand ... any further un-smooth surface deep within the Intake Ports) ... they aren't all that deep; though.

    When I had the Head off my 900 I did some "Hand Sanding" to Polish-up the Intakes and Exhausts. My focus was to Polish the Combustion Chamber and the Tops of the Pistons to prevent Carbon Build-up on the Crown and around the Valves.
     
    RickCoMatic, Dec 14, 2007
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