Discussion in 'Engine, Fuel and Exhaust' started by 00BUCKSHOT, May 10, 2009.


    00BUCKSHOT Junior Member

    whats up with the cranks having .030 to .040 run out?i been hearing about this problem is it very commen?i was think of buying a new bike next year but the crank deal has me thinking buy anouther 88twincam lol
  2. Bud White

    Bud White Well-Known Member Retired Moderators

    supposed the 07 and 08 96's can have a crank runout prob from the crankhalfs twisiting but is supposed to be fixed in the 09's from using the SE crank.. so far no probs with my 08 i dont have near the miles smitty does but hard accels yepper that would be me
  3. dolt

    dolt Senior Member

    '04 was the last year for forged cranks; '05 cranks were cast but I don't know who the manufacturer was. I believe it was '07 when the cast cranks started being made in China and that was the year that the MoCo increased the factory runout spec from .003" to .012".

    As you would expect with a product made in China, QA/QC is lacking and there are probably more out of spec cranks ending up in the later models than there have been in the past.

    If Stage I is as far as one goes with upgrades, most will hold up. However, increased displacement, longer cams, headwork and more compression would force me to have the bottom end beefed up, ala Hoban style, as part of the build.

    00BUCKSHOT Junior Member

    allright from the feedback i'm thinking as long as you leave the motor alone and ride it like you got some sense you should be fine with a twincam96
    looks like there may be a 2010 roadking in my future!
  5. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

    Excellent. As mentioned above, the new bikes are using the SE cranks that seem to have a much tighter press on the crankpin.

    The problem developed when the MoCo changed to the pressed crank where the crankshaft halves were pressed on the crankpin with no welding of the pin. Hard acceleration and deceleration on the 96" and larger bikes seemed to have some problems with the crankshaft twisting on the crankpin causing excessive runout. In extreme cases, this was bad enough to crater the oil pump. As mentioned above, up-grading to the gear drive will definitely be a problem with excessive runout. The Andrews and S&S kits describe how to check for runout, so it must be important.

    See here:

    Consideration when looking at bikes with 96ci or greater - Harley Davidson Community