Check those pulley bolts

Discussion in 'Dyna Models' started by R_W_B, Mar 27, 2012.

  1. R_W_B

    R_W_B Senior Member

    Guys I wanted to share this with you. Saw it on another forum, this happend just 2 days ago, but I've seen at least 6 different reports of it over the past 2 yrs. Belt pulley bolts shearing. (on bikes without the rubber damper drive)

    [---begin insert from another forum.
    I just had that happen today at about 65 mph. Cruising down the 4-lane and I heard something. Thought I might have hit something then a little further down the road I heard and felt something let go and bike started to slow down. Pulled over and friend pulled up behind me and said a bolt hit his leg. Sure enough all the bolts were gone and sprocket free wheeling on axle bolt. We just changed the rear tire last fall and used blue loctite and torqued to specs. ---] end insert

    Pulley bolts are part of my pre-ride inspection ever since I first starting hearing of this long ago. I would suspect these bolts don't just unscrew real rapidly but are loose for sometime before they get out far enough to shear on the swing arm.

    Also if my pulley comes off during maintainance, "new" bolts go back on not the old. (Grade 8 of course). And yes Red loctite. A torch to get them off is a small inconvienence. I know guys that put chrome pulley bolts on. Not me, the grade specs on chrome bolts are to ambiguous.

    Hopefully when this happens the bolts will continue to shear and not lockup the wheel and kill somebody. Ride safe my friends.
  2. dbmg

    dbmg Experienced Member

    Thanks for the heads up RWB.:s
    I have seen this a couple of times while working at a Harley Dealer. You could tell that in both cases there was a new rear tire from another service facility. So there is the possibility that the torque was not checked when wheel was off. On one bike we knew the rider was notorious for doing burnouts....:newsmile077:
    Go figure...
  3. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    Happened to the dyna my wife rides
    I riding behind her heard a metallic rattling sound as she was moving ahead of me got her to stop and checked over the bike found that the rear pulley was loose
    i got my tools out and tightened all the bolts up 1 at a time move bike forward to get to the next one
    got home ok wheel off new bolts blue loctite and torque wrench re check the next 5 riding days of the bike
    The previous owner of this bike has helped greatly increase my knowledge of hd motorcycles as i put right all the stuff he did wrong

  4. Dswartz

    Dswartz Active Member

    It's alarming to me how often this happens. I had a good friend that had all five of his bolts sheared off as well. Fortunately the dealer was able to remove all five broken bolts and he didnt have to purchase a new wheel. I'm not sure if the bolts started coming loose or were just weak for some reason. I know those bolts receive alot of stress from the torque of the motor but I cant believe it's enough to snap all of them.
  5. R_W_B

    R_W_B Senior Member

    Dswartz I don't think it's the engine torque shearing them off. It's just that when they back out (unscrew) far enough they hit the swingarm and at speed that is just too much shear for the bolt shank to resist.

    And thankfully so, since if it did not shear off the wheel would lock up and bodily harm would become a distinct possibility.