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Head Porting...What is the True Value??

Discussion in 'Motorcycle Tech Talk' started by JohnnyBiker, Sep 26, 2011.

  1. FLHTbiker

    FLHTbiker Moderator Staff Member

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    I know was just busting your chops :D
  2. Lucifer

    Lucifer Well-Known Member

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    Good Porter....Did you know he doesn't use the flow bench on Street Port packages??
  3. cardboard

    cardboard Well-Known Member

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    Buddy used him last year. I know well about him. He was taught from one of the best.
  4. Lucifer

    Lucifer Well-Known Member

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    Just checking...Seemed to me that if it wasn't done on a CNC machine and tested on a flow bench you didn't think it was any good....Mr. Dorfmans street ports are done by hand and not tested(absolutely nothing wrong with that BTW)...I guessing your buddy had more than a street port done...
  5. cardboard

    cardboard Well-Known Member

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    That was the 1st bike he's built, Hes a diesel Mechanic.........

    Got another buddy that's used him before Oh.

    Scott with Hillside is usually used...
    Unless somebody will not spend any money doing a build, they Bean is used.
    Some folks wanting a build things you can do the whole build for nothin.
  6. JohnnyBiker

    JohnnyBiker Well-Known Member

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    It sounds like the guy I am talking to is stern on just doing a basic stage one port job on these heads. Not interested in a 114 CI" motor... :roflmao: I talked to the wife last night cause she was asking me what the emails about head porting were all about..:eek: Yes I was busted.. I told her that until early April that bike is still mine, even after I get the new bike the bike it is still mine.:roflmao::roflmao: She asked what I was up to and then I told her, she wasn't upset about it all. :D
  7. JohnnyBiker

    JohnnyBiker Well-Known Member

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    OK, now I just got off the phone with Big Boyz. What he had said is that I have an excellent set of heads and there isn't a lot to do to them. He said that he would also port match the heads and also texture the intake to match texture of the heads.. Now I have heard about that before. Also he suggested to measure the combustion chamber to make sure that I have the cc that the factory says that I have. The reason for that is to make sure that I am making the compression that I want which is 10.5:1. He will do this because there are easy ways such as head gasket thickness to compensate for this... I knew that one, but at least I know what I really have.

    Now here is the interesting part. As I have mentioned to BP and also Lucifer that I was toying with the idea of putting the valve train into a complete roller, Big Boyz said that it would most likely not be very cost effective to make power. He went on to say that I just do not have enough lift for that. He went on to say that it may be better if I went to a 44mm CV instead.. Agree or disagree with this last suggestion???
  8. cardboard

    cardboard Well-Known Member

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    Think yet learnin a little ,while yer thinking about doing a build
    Guess Bean sounded pretty good listening to Jim
    Bean knows his stuff
    Before long he will be covered up with work
  9. baggerpaul

    baggerpaul Well-Known Member

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    i think its not a bad idea if you think you are going to pull that much cfm in to the motor with the flow you got after the intake and cleaning up the castings why not have your carb bored out ? that way you dont have to buy another one?
  10. JohnnyBiker

    JohnnyBiker Well-Known Member

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    I guess I am not sure what you mean by this??
  11. hotroadking

    hotroadking Super Moderator Staff Member

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    picture a hose that is 1 inch, then 2 inch then 4 inch diameter

    It doesnt' matter that it's a 4 inch hose and can pump 500 GPM at 4 inch
    when you can't put 500 GPM in through a 1 inch hose..

    when setting up for performance you have flow, and velocity,

    If your heads flow 600 cfm at 400 lift but the carb only flows 400 cfm, you
    can't fill the heads to volume flow even if the intake can handle 500 cfm.

    it's got to be able to handle the flow from a to z
    and it's got to be able to keep velocity up..
  12. JohnnyBiker

    JohnnyBiker Well-Known Member

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    OK, now that makes perfect sense. What is the cfm of a stock CV 40mm carb?
  13. baggerpaul

    baggerpaul Well-Known Member

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    ill be perfectly honest with you i dont know the cfm of a 40 mm cv . fact is before you make the purchase or modify your carb ask him if he will flow the heads with manifold attached . and send him the carb as well . when its on the bech he can see if the in take ports start to back up on the bench when he's flowing them . if it does not back up on the bench why spend the money on the carb , you follow?
  14. JohnnyBiker

    JohnnyBiker Well-Known Member

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    I got ya. ;) Just curious why he mentions it? I think I am going to have to give a call to someone and see what the flow numbers on these heads are.. Of course I am assuming that those numbers change from engine to engine???
  15. baggerpaul

    baggerpaul Well-Known Member

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    i say screw it leave it alone lets build a new core with a 4 inch arm and a four inch bore !!!!!we can get a used sportster core , off ebay what ya think
  16. JohnnyBiker

    JohnnyBiker Well-Known Member

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    Not for this bike....;)
  17. Lucifer

    Lucifer Well-Known Member

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    Good idea there...you want as small a carb as you can for intake velocity as long as it isn't the bottleneck...only problem I had on a 80" build with the stock CV was when I was pulling past 110MPh it ran outta gas:angry:...after double and triple checking the float level...the only thing I could come up with was the fuel bowl was too small...put on a 42 Mik with a deeper bowl than the CV and it never happened again....
  18. JohnnyBiker

    JohnnyBiker Well-Known Member

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    Hey, this all makes no sense. You guys are talking about speeding up things, possibly enlarging them, but them you say not to increase the fuel??:wtf: More fuel, more power... Especially if your engine is efficient enough to handle it.:banghead:
  19. Lucifer

    Lucifer Well-Known Member

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    The fuel was increased and sucked in really fast...that's why it ran the bowl empty( bowl too small)...the air will be sucked in at a higher velocity through a 40mm opening than through a 44mm opening...bigger ain't always better....if the CV40 will feed enough air for your heads the intake charge will have a higher velocity than if you ran a CV44
  20. JohnnyBiker

    JohnnyBiker Well-Known Member

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    But what you are saying is pretty much dependent if the heads are capable of flowing the cfm or not.. Agree????

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