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  1. #1

    Default ironhead performance impossible?

    I have always had Evo big twins. I know what I can do to improve performance and at what cost. They are the best all around engine for performance and reliablity. This is pretty much a industry given. A few months back I aquired a 74 ironhead sporty for a rediculous price. As always once I started to clean it up and get it running, I started changing and "improving" what I had. Next thing I know, I have a 4" hardtail stretch with a 2003 front end, choppershox seat pan and shox......well you get the picture. It is coming down to the enging now and I am looking for a little more performance out of a 1000cc iron head. Everyone I am talking to just depresses the hell out of me. I know I'm never gonna run in the "Evo class" of chops, but I want to run close. I want to surprise and maybe even spank a few loud mouths big dollar chops with a budget built ironhead. It has a really cool stance with all right add ons, but no horsepower.

    I am hoping someone out there can give me some ideas on a good ironhead performance set up. I don't want to have to fix it every weekend, but I'm not scared of a little valve adjustment on accation. I even had a guy at the machine shop talk me out of head work. He said I was waisting my time. Fucking people used to race these things. I know they can produce horsepower. I guess I'm looking for reliable horsepower. Not a ton, just 80 reliable HP.

    Cams? Head work? Carb? Pipes? Ignition? Breather? Gearing? Can you actually increase cubic inches without stroking them? I'm at a lose. Appreciate any ideas.

    Thanks, Bill
    Attached Thumbnails Attached Thumbnails Unknown.jpg   2011-08-11 18.53.54.jpg  

  2. #2

    Join Date
    Jul 2010
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    cant help you, interested myself actually, but thats a clean bike and a shiny motor

  3. #3

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    Dec 2009
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    Yes to all of the above. Look up pics of Harley drag bikes from the 70s and 80s. Almost all Ironheads. You can do everything to them. Cams, dual plug it, high compression pistons, port, polish, change gear ratios, you name it. Start with a nice mild cam (Y grind is a nice mid to upper range cam that does not require head work, but you want at least 9:1 compression). Then put a nice ignition in it, make sure your pipes are not shorter than 30" (old timer told me that seems to be correct, though I couldn't tell you why other than super short pipes are never good for horsepower/back pressure), and a 2 into 1 also seems to give these guys more umph. Make sure you have a good carb, a lot of people will swear by a S&S, but a CV kills it on these things. If you must run a S&S make sure you do the air bleed mod to get rid of the flat spot in the mid-range. My IH would eat a 1200 sporty for breakfast with just a CV, 2-into-1 exhaust, and a Crane ignition, all with stock "p" cams. The only thing it had was more top speed, which is a given with an extra gear over me. Just dive in, no matter what you are going to be wrenching on it. As long as you aren't dumb, you won't fuck up the motor any more than you would ripping the piss out of it stock (i.e. if Andrews says the cam is for a stroker, don't run it). The biggest thing with a Ironhead to keep it running is to maintain it properly, and listen to it. The motor is so primitive, you can hear everything going on inside of it, if something doesn't sound right, shut it off, and figure it out! Dive in and play though man. Also a good place for more info is XLForums.com. Go straight to the Ironhead section, those guys know their shit. Good luck and have fun my man.

  4. #4
    NHMike
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    Joe at Righteous Cycles was telling me about "Shovester" drag motors. An Ironhead Bottom end and Shovel Heads. Sounds pretty fucking bad ass to me!!

    make sure you let us know what you come up with!

  5. #5

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    May 2010
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    This spring I was drinking with a couple guys that had 11 second quarter mile Ironheads. I was pretty drunk; so I have no recollection of what they did to them. I'll see if I can get a hold of one of 'em.

  6. #6

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    Nov 2010
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    as MileHighMurdercycle said get a CV carb, some "mild" cams and let it breath out through a 2-1 and you are straight in evo country.

    a good dailed in stock ironhead engine with CV and proper tuned exhausts will smoke a stock 1200 evo sporty (dailed in) at short sprints.

    paramount for a good running IH is valve adjustment, make it second nature to often check and readjust your pushrods.

    and first thing you should do is change your oiltubes to the heads for braided lines, it will save you a lot of oil spills...

  7. #7

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    Another thing to remember when dialing in your ignition, is that the timing mark on the crank is a starting point to tune it. It is retarded from where you will want to run it. Start it at static, and advance it from there till dialed. I didn't realize this till a local vintage Harley specialist told me this very trick. Went home and advanced it about 4-5 degrees and it was like a whole other beast.

  8. #8

    Default

    Thanks for the info. You know I had heard somewhere before how well IH's respond to CV carbs. You just verified it for me. I actually have a 40mm CV carb on a shelf in my garage. I also heard that IH's don't respond well to singlefire ignitions. We put one in a friends IH and and nothing but trouble. We switched it for a Crane HI-4 dual fire and perfection. I've run a single fire for years in my Evo's and no trouble. As far as the pipes go, I know you want have good back pressure. Good pipes are freaking expensive. My brother made me a set that look good, but are not the same length. The back ppe is 24" and the front pipe is 36". I don't know what this will do to performance. I was thinking I could use torque cones, like I've used on Evo's before.

    So I guess Y grind cams are a good cam that doesn't require head work. What cams would be good with some mild head work? Or would I be better off leaving the heads alone? Bang for buck.

  9. #9

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    Quote Originally Posted by Hendrixbilt View Post
    Thanks for the info. You know I had heard somewhere before how well IH's respond to CV carbs. You just verified it for me. I actually have a 40mm CV carb on a shelf in my garage. I also heard that IH's don't respond well to singlefire ignitions. We put one in a friends IH and and nothing but trouble. We switched it for a Crane HI-4 dual fire and perfection. I've run a single fire for years in my Evo's and no trouble. As far as the pipes go, I know you want have good back pressure. Good pipes are freaking expensive. My brother made me a set that look good, but are not the same length. The back ppe is 24" and the front pipe is 36". I don't know what this will do to performance. I was thinking I could use torque cones, like I've used on Evo's before.

    So I guess Y grind cams are a good cam that doesn't require head work. What cams would be good with some mild head work? Or would I be better off leaving the heads alone? Bang for buck.
    Y grind doesn't REQUIRE head work is all. Any porting/polishing will only help from that point. The big thing with these is that you can just drop em in with stock springs and such. If you are gasket matching your ports, and polishing the channels anyway, you could step up to I believe a X or XR cam, but you will also HAVE to replace the springs, and measure for clearance. The "Y" grind is kinda the best for a street machine. I'll look for andrews spread sheet and see if I can post a link for ya. Do not waste your money on torque cones. They hold in too much heat right at the head (very bad as I'm sure you know). You are better off making yourself a lollipop at the tail end of the pipes to add back pressure. As for the pipes, if your already fabbing stuff, buy a biltwell kit and make some, you'll save a ton of coin, and be able to make em exactly how you want. If you cruise over to my pics and look under the "Warbringer" album, you can see the 2 into 1 high pipe I made for mine. Sounded AWESOME, and huge difference in off the line power.

  10. #10

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    http://www.andrewsproducts.com/PDF_f...Sport-pg24.pdf Here is a run down of Andrews cams. Sifton also made nice cams too. But Andrews are much easier to get your hands on, usually a little more cost effective, and more popular.


    P.S. From the sheet it says the "R" grind is the next step up with out stroking.

  11. #11

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    Sep 2009
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    I dont know who told you that Ironheads preformance was not on par with big twins. Ironhead and sportster motors came from a preformance design.

    A Ironhead can be made into a rocket ship and should walk all over a Big Twin. That said Ironhead has a weakness and that is the transmission. What is it your exactly trying to get the bike to do and what are you going to use it for. Are you going to ride it as a daily or you just want to win pink slips lol.

    For guys that want to hop up their old Ironheads 1st thing I tell them is make sure the flywheels and rods are solid and make sure you rebuild the trans. no matter what. Skipping on the trans will show you the pain of Ironhead ownership when hopping up the motor and the trans blows your cases apart. Pulling the trans will also let you fix any cracks that might already be in that area of the cases.

    With 60s Ironheads the speedo drive was the cause of the trans failing and gernading. In the 72 and later trans failure was usually due to guys trying to hop the motor and not sorting out the old trans that has been hammered on for the past 20 to 50 years.

    Remember that the flywheels and rods if they need to be freshened up you need to pull everything apart to get to it. Half assing old Ironhead motors is like putting a small bandade over a big cut. It wont last. S odo it right out the gate.

    Transmission I use Andrews gears or OEM. Do not buy cheap aftermarket anything for the trans. You will regret it.
    Cams I use only Andrews Cams unless I send the stock P cams out of the motor to them for a regrind. The stock P cams are excellent cams and if you have Andrews change work their magic on them your in it to win it.
    The old early Sifton cams if you can find a set and right deration for your application are great cams. The new Sifton anything is all junk in my opinion. I know way to many guys that have had the cams leave them stranded.
    Your jugs can be bored to .70 over on the stock barrels. Wesico pistons are top notch and the 10:1 pistons work awesome as long as your rods and wheels are good to go. Wesico also makes S&S pistons now so save the dough and buy Wesico.

    As far as carbs go a lot of dudes swear by CV. I think they work fine on a stocker with exhaust but I use S&S E Shorty Carbs because they are easy to tune and easy to get parts for. They also dont wear out like the CV.

    Preformance wise Makuni all the way. I have ran Makunis on many different motors and bikes over my lifetime. On the built stuff I always find they get the job done. I do know in the Harley world people gasp when they see a Mukuni mounted on one. There are other carbs out their but these are my choices and by no means a must. I must say the Mukuni works.

    As far as head work goes on the Ironheads have a good reputable machine shop in your area that does a lot of HD and has experience with old Ironheads guide you to find the right answer for you. I give this advice because I do not know your weather condition or your altitude or other various factors that come in to play that will correctly answer the head work question.

    I have found what works well in one part of the country does not always work well in another part. A good machinest that has experience in your area will know that answer and chances are your local indy or builders go to him to get the same questions and work preformed.

    Ignitions there are several and I think its really up to the guys budget. I do think the dual plug is a must especially with the crap fuel you come acrossed at some of these boonies gas stops. Anthing to burn the fuel and help cut out detonation or pinging.

    Last thing I see get over looked is the charging system and battery. Cycle Electrics all in one Generator clean up the electrical. Eliminate the old school regulator and relays. Plus they work flawlessly. A good battery is a must especially when running dual plugs.
    I cant tell you how many times I have seen guys buy the best money can buy to put in their motors. Then skimp on the charging system and battery and wonder why the bike misses or acts weird when pouring on the juice.

  12. #12
    garbage
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    Shave and balance the flywheels.

    Duel plug it so you can run higher compression. Domed pistons hate compression.

    Run an S&S if you start doing lots of head work or bigger cams. The slide and butterfly restrict a lot of flow.

  13. #13
    dazegoneby
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    .040 pistons ,,,,,,, ,, oversize,,1,15/16 intake valves,,,1,3/4 exhaust valves, s/s super carb,s/s python pipes,,,unknown size veglia cams,,took a 77 sportster to 140mph,,,this was 1980,,31 years ago ,,musta been overstock compression on pistons,,,, reliable cept the electric starter shit would crap out, on a regular basis,,was my ride for 10 years
    Last edited by dazegoneby; 08-16-2011 at 12:39 PM.

  14. #14

    Default

    Quote Originally Posted by Hendrixbilt View Post
    I also heard that IH's don't respond well to singlefire ignitions. We put one in a friends IH and and nothing but trouble. We switched it for a Crane HI-4 dual fire and perfection. I've run a single fire for years in my Evo's and no trouble. .
    I have never heard this and i was just about to order a ultima single fire unit for mine. Whats the deal with ironheads not responding well to singlefire ignitions?

  15. #15

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    Quote Originally Posted by splattergod View Post
    I have never heard this and i was just about to order a ultima single fire unit for mine. Whats the deal with ironheads not responding well to singlefire ignitions?
    sounds like misinformation,,if you go look at the xl forums it is reccommended..I installed the ultima single fire about a month ago and love it,I have a kick only and it starts so easily and consistantly,idles so smooth,and has such a smooth and consistent bottom end,probably one of the best things you could do to your old ironhead....the ironhead loves single fire.....

  16. #16
    xllance
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    Good asvice there Atomrotton ! And yes singlefire is the way to go in my opinion. My IH is not by any means a hot rod but the Crane single fire and CV carb is the best money I've spent for the motor. But like Atom said get the basics solid before you bump it up. No telling what the POs have put it through.

    Oh yeah a 2 into 1 exhaust too!
    Last edited by xllance; 08-16-2011 at 8:14 AM.

  17. #17
    LivingCanvas
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    Quote Originally Posted by splattergod View Post
    I have never heard this and i was just about to order a ultima single fire unit for mine. Whats the deal with ironheads not responding well to singlefire ignitions?
    I just put an ultima single fire ignition on my ironhead, and the thing has never run better. I think if there's something wrong on other peoples bikes, its because of something they didn't do right

  18. #18

    Default

    Quote Originally Posted by splattergod View Post
    I have never heard this and i was just about to order a ultima single fire unit for mine. Whats the deal with ironheads not responding well to singlefire ignitions?
    I have a ultima single fire in my 80 IH and it runs great, I have tons of motor in it, it will smoke any 1200 evo out there, just wish I had 5 gears and it would be untouchable, Have an ss carb with the air bleed drilled out thing screams down the road. buy it you will get better gas milage and it will not skip a beat.

  19. #19

    Default

    Quote Originally Posted by SMChewy View Post
    Yes to all of the above. Look up pics of Harley drag bikes from the 70s and 80s. Almost all Ironheads. You can do everything to them. Cams, dual plug it, high compression pistons, port, polish, change gear ratios, you name it. Start with a nice mild cam (Y grind is a nice mid to upper range cam that does not require head work, but you want at least 9:1 compression). Then put a nice ignition in it, make sure your pipes are not shorter than 30" (old timer told me that seems to be correct, though I couldn't tell you why other than super short pipes are never good for horsepower/back pressure), and a 2 into 1 also seems to give these guys more umph. Make sure you have a good carb, a lot of people will swear by a S&S, but a CV kills it on these things. If you must run a S&S make sure you do the air bleed mod to get rid of the flat spot in the mid-range. My IH would eat a 1200 sporty for breakfast with just a CV, 2-into-1 exhaust, and a Crane ignition, all with stock "p" cams. The only thing it had was more top speed, which is a given with an extra gear over me. Just dive in, no matter what you are going to be wrenching on it. As long as you aren't dumb, you won't fuck up the motor any more than you would ripping the piss out of it stock (i.e. if Andrews says the cam is for a stroker, don't run it). The biggest thing with a Ironhead to keep it running is to maintain it properly, and listen to it. The motor is so primitive, you can hear everything going on inside of it, if something doesn't sound right, shut it off, and figure it out! Dive in and play though man. Also a good place for more info is XLForums.com. Go straight to the Ironhead section, those guys know their shit. Good luck and have fun my man.
    The newer model S&S E has an air bleed valve that is adjustable. you have to buy a 60 dollar jet kit to do it they dont sell just single jets and they arent normal sizes. but it is there

  20. #20

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    May 2011
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    I have an 80 which I'm trying to sell, switched to back to points. Use a 5 ohm dyna coil. Top end is like .3 over and have a super e with a v stack on it. (It came right off a shovel so it runs a bit rich), but the v stack helped over the normal teardrop and filter. It kills in the low end, hits a flatspot (definitely the jetting) then will accelerate to the point it shakes like Michael j fox and scares the shit out of me. (It's a rigid). I couldn't be happier with an 80 ironhead

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