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1985 Iron Head WHAT CAN BE DONE?

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  • 1985 Iron Head WHAT CAN BE DONE?

    I knew quite a bit about what to do to my 2003 Evo, but I'm clueless when it comes to Iron Heads.



    1985 Iron Head Sportster?

    Big bore kits? Who? Where?
    Deck Heads? Pistons?
    Big Valves?
    Cams?
    Breathers?
    Exhaust?

    Haven't got a clue what to do, or even what can be done. OR WHAT IS WORTH DOING ON THESE?

    I'd like to know what constitutes a very strong stage 1, and what makes a stage 2 on these bikes?

    Any help is appreciated.

    Best regards,

    Fiftysixer

  • #2
    I now know a little more and it looks like doing a stroker job on the engine is about the only real option for performance outside of general stage 1 stuff. So thats out.


    I'll focus on getting the heads completely redone with god components, opening up the intake, possibly chaging the carb for either a Mikuni or and S&S depending on whats best.

    Any thoughts are welcome.

    Best regards,

    Fiftysixer

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    • #3
      cams and higher comp pistons seem to be the biggest performance improvement for these models outside of the big bore/ stroker kits. Not much can be done to the heads
      Bonneville might have beat us this year but that White Bitch is going down in 2017!!!

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      • #4
        I used to have a 85 iron head and this is what I did to mine. I went to higher comp pistons. Sent the heads out to Jerry Branch. Installed better cams. Went to S&S carb. Got rid of stock pipes. Went to a electronic ignition. The bike did not run bad for a 1000cc engine. Good Luck!

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        • #5
          There's a lot of things that can be done. I've got a book at home, http://www.amazon.com/V-Twin-Thunder...v+twin+thunder of course, I've had it longer than internet forums have been around, and I kick myself for giving away a copy 20 years ago after seeing this price. "P" cams are nice, a 2 into 1 exhaust is helpful, as Dan can attest. My old 75 had plenty of oomph without doing anything to it.

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          • #6
            On an ironhead the first priority is digging into it and fixing all of the "repairs " that it has been inflicted with in its many years. Previous owners are usually the worst thing that ever happened to these bikes.
            He who dares not offend cannot be honest.

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            • #7
              My 1976 Bicentennial Sportster was the first time I ported a set of heads. Did that in 1980.

              First, get a dremel and several shape/hardness stones. A flex drive helps to get to the deeper stuff.
              Port match the intake and exhaust and use the stones to eliminate casting junk in the ports.
              Leave the intake rough and smooth the exhaust.
              Get rid of any sharp angles in the ports and combustion chamber; nice round edges work.

              Take your time, cast iron takes a lot more time and energy than the aluminum heads I now work on but the principle is the same.

              Z

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              • #8
                Heads, heads, heads. Heads and cam shaft are the key to HP. Exhaust is easy and cheap, Harleys don't seem to be too particular on length or tune, as long as they are short and open. Dyna ignition is also cheap and easy. Mikuni is still a good bet on carb, don't over jet. Every cowboy with a Harley thinks they have got to go bigger jets, I have gone down as much as 10 sizes on Sportsters I have bought and gained top end. The iron head motors are bullet proof if built right, if you are serious racer invest in a Dyna rev limiter, cheap protection against missed shifts and over exuberance.

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                • #9
                  Zach, above, has got the right info on head porting, a big time racer in our area says heads and exhaust are not a science they are zoodoo. Experience counts, I have ruined several sets of heads by hogging out too much. Find a local with a flow bench, run your stock heads then run your ported heads, aftermarket may be cheaper and wiser. A little roughness on the ports leads to turbulation, a good thing.

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                  • #10
                    S&S has a really great series of vids concerning carb jetting and exhaust pipe selection. Just google S&S carb tuning and the location for the whole series of vids should come up, one will lead you to the rest. I was trying to figure out the tuning on my series B with the added Thunderjets. This ain't your brothers Mikunis. Hell, it is a lot easier than synching four asian carbs.

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