Can a 98" Twin Cam engine be stroked to a 107"

Discussion in 'Touring Models' started by mlemay, Jul 28, 2016.

  1. mlemay

    mlemay Member

    64
    18
    2
    I currently have a 98" big bore motor. The 98" kit was put in when the 95" started burning some oil. When it's time to rebuild the bottom end, can this be converted to a 107" just by adding a crank with a 4.375 stroke? Do pistons and connecting rods need to be changed? The engine is in a 2004 FLHRS.
     
  2. dolt

    dolt Senior Member Contributor

    1,814
    83
    203
    Yes; however, you will need new pistons with shorter skirts; rods are the same. If you rebuild the lower unit and are considering the longer stroke, might as well case bore for 4.125" cylinders and build a 117" motor. Case boring will run about $300; MTC will sleeve your OEM cylinders, hone and fit a set of their pistons for $400-$500. A set of S&S cylinder will run about $600; add pistons though. Might as well have crank trued, balanced and pinned and Timken main bearing installed, another $800 or so.

    Some $$ for sure but once you pull the lower unit, might as well go big. I built an all bore 107" motor a while back and have been kicking myself ever since; should have stroked and gone 117". The 107" motor is no slouch at 124TQ/110HP but knowing I could have had more performance for another $1000 has been bugging me for a while now. Very tempted to take her down again and rebuild bigger but I can't justify tearing down a motor that runs real good and has lots of life left.:confused:

    Don't be that guy......;)
     
    dbmg likes this.
  3. mlemay

    mlemay Member

    64
    18
    2
    Thank you for the info. I hope the bottom end stays together until I can afford to go big.