Exhaust ports

Discussion in 'Harley Davidson Extreme Modification' started by AliveAgain, Aug 22, 2011.

  1. AliveAgain

    AliveAgain Member

    I just put my stock head together after lapping the valves in. I have two questions that I hope you performance people can help. The exhaust port seems to have a slight hump and then a nice size dip to meet the opening for the exhaust pipe connection. On my sport bike, it is more of a smooth elevated flat surface on the bottom section. The Harley port looks like the gases will start tumbling before the first bend of the exhaust pipe. Won't this hamper the flow and scavenging effect?

    Second question concerns the valves. They don't even look like multi-angled seating faces and actually have a lip just past the seating face on the valve. I thought that reduces flow. On any head that has been reworked for better breathing, do they address these issues or is there some reason for them to be there?
  2. nitroracer

    nitroracer Member

    what year are the heads? basicly all HD heads need a fair amount of work to get flowing,the seat placement & valve jobs are not aimed toward performance.we like to D shape the `05 & down ex ports,& all seat work should be done on a precision machine (we use a SERDI 100 seat & guide machine) for perfectly radiused seats (very important to flow)
  3. AliveAgain

    AliveAgain Member

    Yes, the D shape was what I was referring to on the port floor. My bike is a 2006 dresser and am not looking for all out performance but definitely saw a difference from my other bike (2000 zx12r). I figured people in the performance end would be able to fill me in. Do any aftermarket heads have the ports reconfigured or are they more for big lift and bigger valves? At some point, I'll want a 95" kit and the heads to go with them.
  4. Jack Klarich

    Jack Klarich Expert Member

    Bishop's Performance - Heads Here is a good read I stumbled onto

    BUBBIE Well-Known Member



    It is probably Better and cheaper to Use the heads you have and Just have some work done to them... IMHO

    I know and TRUST a good head man in my area of Washington in Edgewood... Don "Dewey's Heads".. I have been to his shop and looked,,,Very NICE set-up... He Knows a Lot and does a lot of Heads.... I will use him to do my work when I tear into my 09 FLHR.
    (if you want more information on getting in touch with Don, PM me)

    This is where you TALK LIVE (phone) with your Head Porter and then you get what you are after...

    Telling the Porter WHAT you want out of your bike and What you are going to use to get it there, WILL determine what HE Needs to do with the head work and How Much Needs to be done to accomplish YOUR Needs.. :bigsmiley14:

    I like this approach to head work as it is MORE individual style and will FIT your bike and needs,,, Much better than a one head fits all application.