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Thoughts on engine plans?

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  • Thoughts on engine plans?

    Plan on going with the 1250 conversion, stock cams, stage two 883 heads. I'm a beleaver in less duration more flow over more duration and less flow. Guessing it will be good for 74 whp or so at around 5700? Bike is a 2016 iron with V&H twin slash mufflers, SE intake, FP3 programmer.

  • #2
    Or maybe mid 80s hp. What would match my old, stock XB12s

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    • #3
      I would hope for low 80s with that package. The exhaust will have a lot to do with the numbers.
      Bonneville might have beat us this year but that White Bitch is going down in 2017!!!

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      • jkhawaii
        jkhawaii commented
        Editing a comment
        I still have time to change my mind and get some cams. Going to be collecting parts for a few months at least.

    • #4
      I have made over 74 horses easy on the cheap with 883 to 1200 conversion kit keith black forged pistons, stock 883 heads, ebay cam swap, carb tune. I have been riding and racing the sportster for over 41 years. I just have never seen the need to waste money for the 1250 kit shit when you can make what little hp gained elsewhere cheaper. What I like about the KB forged conversion pistons is, if you want to go with 1200 heads, the pistons have dual valve reliefs. Dan is right about the pipe. I have an LSR on one bike and it is the mac daddy.
      Last edited by stocker; 06-29-2017, 02:03 PM.

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      • #5
        Originally posted by stocker View Post
        I have made over 74 horses easy on the cheap with 883 to 1200 conversion kit keith black forged pistons, stock 883 heads, ebay cam swap, carb tune. I have been riding and racing the sportster for over 41 years. I just have never seen the need to waste money for the 1250 kit shit when you can make what little hp gained elsewhere cheaper. What I like about the KB forged conversion pistons is, if you want to go with 1200 heads, the pistons have dual valve reliefs. Dan is right about the pipe. I have an LSR on one bike and it is the mac daddy.
        I don't understand how you could use the same pistons for both 883 and 1200 heads? The 883 heads have only 49cc chambers and use a dished piston to get around 10:1 compression. The new 1200 heads have 62cc chambers and use a flat top piston to get around 10:1 compression. Older 1200 heads have even bigger chambers. The valve reliefs are not the issue.
        Bonneville might have beat us this year but that White Bitch is going down in 2017!!!

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        • #6
          Originally posted by stocker View Post
          I have made over 74 horses easy on the cheap with 883 to 1200 conversion kit keith black forged pistons, stock 883 heads, ebay cam swap, carb tune. I have been riding and racing the sportster for over 41 years. I just have never seen the need to waste money for the 1250 kit shit when you can make what little hp gained elsewhere cheaper. What I like about the KB forged conversion pistons is, if you want to go with 1200 heads, the pistons have dual valve reliefs. Dan is right about the pipe. I have an LSR on one bike and it is the mac daddy.
          I have a 2016. Can't bore the cylinders

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          • #7
            Originally posted by NRHS-Dan View Post

            I don't understand how you could use the same pistons for both 883 and 1200 heads? The 883 heads have only 49cc chambers and use a dished piston to get around 10:1 compression. The new 1200 heads have 62cc chambers and use a flat top piston to get around 10:1 compression. Older 1200 heads have even bigger chambers. The valve reliefs are not the issue.
            They have different part numbers for different compression ratios. Since compression is the issue. One part number will give you 11-1 compression with 883 heads. 1200 heads bring it down around 10 to 1. They offer dished versions too. We never had a problem with them. Depends on what the plan is. Check out the KB website. I never liked the two piston will fit everyone theory. You can get as low as 8.5 to 1 if you want. Makes swapping heads simple, and ya keep the piston. Aaron always pushed the crap if ya use the 883 head you are stuck with the head...yea...if ya don't know how to get around that from the beginning.
            Last edited by stocker; 07-02-2017, 08:55 PM.

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            • #8
              Originally posted by jkhawaii View Post

              I have a 2016. Can't bore the cylinders
              That's right. I don't use any cylinders over 06 or I use aftermarket.

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