103 Big Bore Kit

Discussion in 'Harley Davidson Extreme Modification' started by KingHeritage, Oct 27, 2008.

  1. KingHeritage

    KingHeritage Junior Member

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    I've been considering installing the 103" big bore kit on my '07 Heritage.The local dealer is drumming up winter business with special prices(though I haven't gotten an out the door price yet).I'm already running V+H true duals,SE air cleaner and PCIII.Will this upgrade be worth the money versus the performance I will receive?
     
  2. USMCCWO5

    USMCCWO5 Junior Member

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    My opinion only: No!

    If you upgrade the heads with larger valves, port & polish, bump the compression, then you will see a performance gain vs money spent.

    However, if the price is right, that might be a good place to start, especially with the right cam choice.
     
  3. USMCCWO5

    USMCCWO5 Junior Member

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    Good call on the complete kit, especially the clutch improvement.

    If someone says they have 100 hp, ask them if they have a stock clutch. I don't think both of them are compatible. My stock clutch didn't make it passed the dyno work. My next stop was Primo-Rivera.:newsmile105:
     
  4. FishHunter

    FishHunter Active Member

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    A great upgrade is to bore to 103"(or to a 3.935" bore, 107") is to compliment that with a Wood 6 or 7H,(requires a valve spring) and have 1.900" intakes installed, and set the compression at 10-10.25:1, along with a Zippers air filter. Big early torque, and with a good exhaust, also have the ability to mark an hp number as well. Good combo.
     
  5. spartacus55

    spartacus55 Active Member

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    just had 103 kit installed on my 2007 road king already had rinehart tru duals se hi flo air cleaner and sert. added se flat top pistons, se cylinders. 255 cams, heavy duty clutch spring, assorted springs and gaskets. After dyno tuning went from 67hp and 70 ft/lbs tq to 95 hp and 100 ft/lbs tq runs and sounds great cost 1590 dollars including dyno time.
     
  6. r2kvet

    r2kvet Member

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    A couple months ago, I got my Dyna upgraded with the Stage III 103 kit straight from the H-D Racing catalog. Fantastic results. 100HP at 5,500 RPM and above 100 torque from 3,000 to 5,000 RPM. Beside the bigger displacement, I had upgraded the air cleaner and replaced the exhaust for the Screaming Eagle exhaust (for the look not the performance).

    Lovely.

    R2KVET


     
    Last edited: Mar 29, 2009
  7. jims87flh

    jims87flh Banned

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    I have an 80 CID motor, punched and streched to 89 CID, runs pretty well, but if I wanted to upgrade, what would y'all suggest? I know I'll likely be getting a heavy duty clutch soon already, so engine upgrades please?
     
  8. jims87flh

    jims87flh Banned

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    Head work as in new heads, or as in machining the heads?
    I'm only getting about 25 MPG now, seems a bit light, I expected at least 30, although I do tend to drive faster than traffic, and jack rabbit start a lot cause I love the sound of my motor/exhaust. Suggestions?
     
  9. Street Bagger

    Street Bagger New Member

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    Hi all.... New guy here.

    I am in the process of installing a 103 stage II on my 08 Street glide. I have it all apart, new pistons on the rods and ready to go back together with it this weekend.

    So far it has been an easy task, and look forward getting it finished up.

    I bought all the software to re-map the ECM. I have the older race tuner on the bike.

    I will keep everyone informed and Have enjoyed reading and learning about all you scooter trash.

    Im out
    Michael
     
  10. R. Lewis

    R. Lewis Senior Member Retired Moderators

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    You know we NEED pics.!!!! Good luck with it!