Twin cam crank failures

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  • ausvelle
    ausvelle
    12 years ago

    Whats the go with crank failures on twin cam engines ? I live in small country town and know of 3 that have crank problems the last is spun crank at 20000 ks this bike broke engine mount at 8000 ks then again at 20000 Harley would not fix second one cause just out of warrenty then owner found crank has spun two other bikes with low ks have also had problems one wrecked cases these guys are not new to V twins long time owners over many years Shovels, Evos  Etc does anyone else know of other twin cams doing this

  • nhb006
    nhb006
    12 years ago
    The small country town wouldnt happen to be Mildura by any chnace?
  • AJ56
    AJ56
    12 years ago
    With the new cranks in the Twin Cams they suffered from sizzoring due to the way the cranks were manufactured. Originally .003" was the limit but HD were getting a lot of cranks coming back so .015" was the acceptable limit. Pretty piss poor in my view but what can you do. I think it is luck of the draw as well. Crank made on a Monday Morning or Friday Afternoon were failing big time. :)
  • HogBag
    HogBag
    12 years ago
    Its a crape shoot with cranks but I have never seen one fail in my country town. One of my mates rides his bikes hard of the show room floor smoking tyres at every opportunity and he has had zero problems with 4 HD's riding hard. I'm sure if your a engine lugger your motor will scissor the crank cruising at 100 KPH at 2400 RPM in 6th gear. Flog it and don't worry
  • ausvelle
    ausvelle
    12 years ago

    No its not Mildura just south of the Gold Coast The bike with 20000 ks on it is riden on club runs often, as to oils I do not know but its been to a certen dealer around here for services I just thimk that its always had a problem who else has broken 2 mounts in that kms range?

  • Retroman
    Retroman
    12 years ago
    I've worked on LOTS of twin cams and have never seen crank problems here in the west.

    I have heard 3rd and 4th hand, but that may be urban myths ?

    Engine mounts on Dynas : Different story there

    I have personal knowledge of these failing and being replaced on bikes well under 1 year old ( warranty of course !)

    And I sit at 100Km/H in 6th on my bikes all the time with no dramas going back to 2006 ( the first 6 speeds on Dynas !)

    With all the "up the arse cameras" here in Perth now , 110Km/H will get you busted sooner or later around the metro area.
  • kimosabee
    kimosabee
    12 years ago
    This is my first post, but take it for what its worth:

    There seems to be a lot of heresay and potential misinformation posted above on Crank failures and very little real world experience.

    Having had 2 cranks scissor on MY 07 St Bob and a 07 StreetGlide, there has been significant crank failures on the first of the 96 motors. This can be eaily verified by research on other bike forums in the USA. First crank bent because i downshifted too quick on a 130HP+ St Bob and the second crank was on a demo St Glide. Runout on the crank was 29thou. Harley did indeed change the run out spec on cranks to 15thou due to the large number of bikes coming back for warranty claims on shitty cranks.

    Downshifting was the quickest and easiest way to make a crank shit itself. Take out oil pumps and make messes of engines. I know for a fact that my Dealer in WA replaced 7 cranks on top of my 2 in the years 06-08. The dealers and HD Australia wouldn't admit publicaly that the first years of the 96 motors had crap cranks. They just changed the spec and replaced cranks and other damage under warranty. The 09 bikes had a different crank manufactuer and there has basicially been zero crank failures reported since then. Mind you- changing the run out spec helped. To stop this problem, a lot of us over here and in the USA went to Darkhorse prepped cranks and put the Timken bearings in the lower cases.

    I remeber talking to my Engine Builder in the USA in mid 2008 and he had a brank spanking new CVO Ultra come in with 78 miles on it. Guy reckoned the bike felt funny. Dial indicator was put on the crank and it was 34thou from the factory. HD replaced the whole motor as the owner took it out on the street and just slammed a big downshift on the new motor and destroyed it.

    Anyone with a Sept 2008(09 Model) or later bike should be fine. Each time we do an engine build, the crank run out is the first thing we check. Just my first hand experience and 2 cents worth

  • grim
    grim
    12 years ago
    I guess if you look at the basic crank design there is a real chance of failure under heavy loads or engine mods that put more pressure on the crank. Harley run a three piece crank that is pressed together, I know of a few guys that have stripped their motors ,trued the crank then tig welded the pressed joints ,b4 carrying out other engine mods--one piece and slipper bearings would be the go--cheers Grim
  • grim
    grim
    12 years ago
    I guess if you look at the basic crank design there is a real chance of failure under heavy loads or engine mods that put more pressure on the crank. Harley run a three piece crank that is pressed together, I know of a few guys that have stripped their motors ,trued the crank then tig welded the pressed joints ,b4 carrying out other engine mods--one piece and slipper bearings would be the go--cheers Grim
  • grim
    grim
    12 years ago
    why did i put that in twice--cheers Grim
  • Retroman
    Retroman
    12 years ago
    St Bob and a tourer ? That narrows the "who" hahaha...

    Good post kemosabee. I just haven't seen any "bad cranks" myself. I did hear the rumbles tho'...

    Wouldn't surprise me if the dealers did a "quiet" campaign to negate any bad publicity

    Over and out

    "Tonto"
  • FLSTC
    FLSTC
    12 years ago

    honestly , the mods should ban both the OP and kimosabi .  this is utter horse shit and does nothing for this site.

    If this was posted in the HD Forum in the States they are quickly howled down and banned .  I cant recall any decent ( ie long term/reliable) member of the HD US forum ever having this problem . And their membership probably measures in the 100,000's

     

  • FLSTC
    FLSTC
    12 years ago

    this thread needs to be deleted

  • AJ56
    AJ56
    12 years ago
    I expect it is governed by luck and how you ride the bike. Hard Accel and banging back through the gears is going to do something in the end. And as Hilly says it may happen and then rebuild and do the crank.
  • jon doe
    jon doe
    11 years ago
    you,s are stressn me out ,, ive got an 07 build 08 street glide with a factory 103 kit and 255 cam ... hope my crank dont shift ..
    J.D.
  • jon doe
    jon doe
    11 years ago
    and a 09 street bob build date november 08
  • kickinon
    kickinon
    11 years ago
    first hand experience this week with joes 2007 96ci softail std. with 50,000km
    took the cam cover off & the cam chains are worn badly as well as the adjusters, the cam plate bushing has worn through on one side, the oil pump gears are bad with rub marks, dial indicator reads pinion shaft run out at 0.040. he bought the bike new, the verdict is flywheels are out of true, a Harley Dealer quoted $5K ish, probably a little more to fix it, to purchase A scream'n eagle short block (cases,flywheel ass.oil pump) to fit the rest of your partsto cost $2.5K with discount brings it down to about 2.2K if he does the work himself which is what he plans on..My 2006 88ci streetbob with about 50,000km has never missed a beat, havnt had a motor cover off it since new, its been thrashed plenty.when l get back from a 4K trip next month i'll take a look behind the cam cover out of curiosity. oh yer theres plenty of used twin cam cranks out there for sale.., MY 2 CENTSWORTH IS l think its a design fault, And a pressed in crank pin(twin cam) as aposed to the older style keyed and bolted (earlier HD's) just isnt the right manufacturing process, l know why its done,,,,,costs..
  • 78gold
    78gold
    11 years ago
    Hilly,
    Glad to hear yours is doing well.
    I have an 06 Lowrider with 115,000k's on it,
    Not sure how to check myself but will get checked soon.
    Just did an oil change, plugs and cleaned A/cleaner so will be a couple of thou before I get checked.
    Ride Safe
    Nigel
  • Spook
    Spook
    10 years ago

    I have a TC88A in a Road King. The original owner, known to me, did I understand return the bike for a recall on cam problem and I assume this was the problem being addressed here. The poor bugger died so I can't ask him now.

  • 13Deluxe
    13Deluxe
    10 years ago
    I reckon there may be one too many zero in there Trent. Did you take a picture of dial gauge? My runout was 0.075mm, converts to 0.0029" or just under 3thou. However I could be wrong I've only ever really used metric.
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