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  1. #1
    Senior Member TheDullCarbide's Avatar
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    Help me port my head!

    I know the motto is "Smooth the short side, leave the roof alone." My roof seems a little low to me. How should I treat it?

    100_4439.JPG
    Last edited by TheDullCarbide; 07-07-2018 at 03:11 PM.

  2. #2
    ole4's Avatar
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    The shortside on these heads is too short between the seat and the runner so about all you can do is to put a nice radius on it. Because it is short the radius will be small but unless you fill the floor to raise it and give more height for a better radius just round it up. The roof is very important and yours looks particularly nasty as in the area around the valve guide is massive. Here are some pics but this head has a 32mm intake so yours will not be as big. DSC00469.JPGDSC00465.JPG
    Ole

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    Senior Member TheDullCarbide's Avatar
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    Quote Originally Posted by ole4 View Post
    The shortside on these heads is too short between the seat and the runner so about all you can do is to put a nice radius on it. Because it is short the radius will be small but unless you fill the floor to raise it and give more height for a better radius just round it up. The roof is very important and yours looks particularly nasty as in the area around the valve guide is massive. Here are some pics but this head has a 32mm intake so yours will not be as big. DSC00469.JPGDSC00465.JPG
    Thanks for the tips ole4! You've been the biggest help teaching me about these engines.

  4. #4
    Senior Member TheDullCarbide's Avatar
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    Here's the after photos. I did round the short side all that I could. I'm wondering if it is a good idea to shorten the valve guides a bit. Keep in mind this is going on a hopefully semi-reliable 7k-ish build.

    Sorry for the shitty photos. I need a new potato:

    100_4856.JPG

    The intake:

    100_4864.JPG

    The exhaust:

    100_4870.JPG

  5. #5
    ole4's Avatar
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    Looks a lot better.
    Ole

  6. #6
    Senior Member DeadPixel's Avatar
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    ported 2.pngported.pngProject4.pngProject5.png

    I like to use 80 grit emery that's about 1/4" wide. I pull it through the port to round out my short side. Its a little different than what most do but it works for me. The head in the picture was cleaned up around the valve guide with a carbide bit on a dremel than smoothed out with the emery I rolled up by going through the port. I used a screw driver to put pressure on the emery from above. The emery was through the port and the screw driver that I used to push down for pressure was through the valve seat so it took 2 hands. Don't put pressure when cutting with your power tool and use a high speed or it will crab and catch. After you port your head if its in your budget I would have some one do a multi angle valve job on your head. I have yet to have one of my heads get a valve job yet but know its one of the best areas to improve flow. Last I was quoted was $30 for a 3 angle on the seat and 2 angle on valve plus the shipping. Also keep in mind what your using the head for too. Don't go open it up too far if your keeping the stock valve size and just building a torque motor. Let us know how this goes for ya. Home something here helps ya.

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  8. #7
    Senior Member TheDullCarbide's Avatar
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    Quote Originally Posted by DeadPixel View Post
    ported 2.pngported.pngProject4.pngProject5.png

    I like to use 80 grit emery that's about 1/4" wide. I pull it through the port to round out my short side. Its a little different than what most do but it works for me. The head in the picture was cleaned up around the valve guide with a carbide bit on a dremel than smoothed out with the emery I rolled up by going through the port. I used a screw driver to put pressure on the emery from above. The emery was through the port and the screw driver that I used to push down for pressure was through the valve seat so it took 2 hands. Don't put pressure when cutting with your power tool and use a high speed or it will crab and catch. After you port your head if its in your budget I would have some one do a multi angle valve job on your head. I have yet to have one of my heads get a valve job yet but know its one of the best areas to improve flow. Last I was quoted was $30 for a 3 angle on the seat and 2 angle on valve plus the shipping. Also keep in mind what your using the head for too. Don't go open it up too far if your keeping the stock valve size and just building a torque motor. Let us know how this goes for ya. Home something here helps ya.
    Never thought of using the sandpaper method on the radius but I guess it should have been obvious. I used a carbide burr and an air pencil grinder. Made my teeth cringe. I learned the hard way to go very light and fast on the tool to not load it up.

    Who quoted you for the valve job?

  9. #8
    Senior Member DeadPixel's Avatar
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    A place called DMD performance. They do kart motors. I have them liked on face book.

  10. #9
    Senior Member TheDullCarbide's Avatar
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    Quote Originally Posted by DeadPixel View Post
    A place called DMD performance. They do kart motors. I have them liked on face book.
    Thanks!

  11. #10
    Senior Member EVOL Tweety Bird's Avatar
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    Well on Tweety Bird I did my own head work. Got rid of all the sharp angles on both ports, even ground down the valve seats to optimise flow. Polished the exhaust side, and really roughed up floor and walls of the intake. Even added to the hump on the intake to speed up the flow to the valve. Be 2 years next month, and still running like the assaulted ape. Did all the other mods too,filter, jets, header, 22 pound springs, cam, billet rod/flywheel. It (head work) worked, I had to increase the idle jet 2 sizes to keep up with the flow.

    Followed a lot of what this guy does on racing motorcycles. Good read if you have time.
    thanx

 

 
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