Riser question

Discussion in 'Dyna Models' started by formike56, Apr 25, 2011.

  1. formike56

    formike56 Junior Member

    Has anybody have there riser bolts shear in two? I had one do this last weekend as I pulled into a stop for gas. Put kickstand down heard a plink looked down there was half a bolt laying on the ground......:sd:sd Thanked god that I was stopped before that happened.
  2. Big Stan

    Big Stan Member

    While I have never had it happen, The most likely culprit was the bolt was overtorqued upon installation.Combined with vibrations exerted by the bike and voila, significant emotional event.
    Hardware, such as nuts and bolts, is designed to distort or stretch to a certain extent without damage when it reaches its designated torque value.
    (they normalize once the force has been removed)
    With that being said, don't fear the risers.
    If you already knew this I don't mean to insult your intelligence.
    If you didn't, well at least one of us has learned something today.
  3. Breeze3at

    Breeze3at Well-Known Member

    I have read of a couple instances of riser bolts breaking. If your avitar is the bike/bars and your signature line is right, I think you have found the cause. :p Big bars and big hp-tq put a lot of stress on 'em. Try grade 8 bolts, and keep on hangin' on tight!
  4. formike56

    formike56 Junior Member

    I'm a machinist by trade. The bolts were not overtightened. I think they were soft. I will be testing the brinell on them tomorrow. The threads weren't stretched at all. When I drilled the remaining part in the riser it was real soft. Like drilling butter. used a easyout to remove it. Spec is 30-40 ftlbs when tightening them. The last set of risers were aluminum with a chrome plating. When I removed the bolts from them it pulled all the threads. This set were manufactured from some sort of steel. Don't know if it is mild steel or 1045, 4140. I should make my own set and heat treat them. I have all the machines to it with here at work.
  5. glider

    glider Veteran Member


    From your avatar pic, it looks like your grips are eye level. That in itself puts a big strain on the riser bolts.
  6. Jack Klarich

    Jack Klarich Expert Member

    If you are going to run higher bars you best be checking all the fasteners more often. They will put more stress and leverage on the front end, kind of like all the kids putting 20 inch wheel on cars that had 14 wheels, it puts way too much strain on critical front end parts, this is not just my opinion, I see it every day at work, check them and be safe:s
  7. Big Stan

    Big Stan Member

    OK well it looks like neither of us learned anything on my last post. (I'm a machinist too)
    So it sounds like you had a manufacturing anomaly in your suspect bolt. I would definitely fab my own hardware if I were you. I have a few hand fab goodies on my bike, and I am prouder of the little "freebies" made from scrap than anything bought from a store.

    I am also curious to know if there is a significant variation in BHN from the broken bolt to the one still intact?
    Last edited by a moderator: Apr 26, 2011
  8. wilks3

    wilks3 Junior Member

    I going to change to studs. Coarse thread into risers, fine thread on bottom. I'm going to check with ARP bolts and see what they can offer.
    Last edited: Apr 26, 2011
  9. R_W_B

    R_W_B Senior Member

    I have heard of it about 3 times before yours. Two of them resulted in crash but no serious injuries since they went into the grass after slowing some. If it happens and one can think about it at the time, the best thing to do is let go of the bars and slowly apply the rear brake while steering by leaning, keep your knees against the tank.

    Next time I have mine off I'm gonna replace them with grade 8's, and replace them every time I remove them thereafter, just like my real pulley bolts.

    Glad you weren't hurt. Pulling into the store for it to break, somebody must be looking out after you. The nearest I could come to that was pulling into a store to realize my rear tire was flat.

    And yes physics denote that higher bars cause a greater pressure on the bolts.
  10. formike56

    formike56 Junior Member

    Had to leave town for a week. Had a family emergency. Today was able to test the bolts that the HD dealer supplied the last time the risers were replaced. The spec for a Grade 5 bolt is 25Rc-34Rc for the core. The one that sheared was at a 12Rc. :bigsmiley21::( Which is half of what the spec is. The one that didn't shear was a 25Rc.:) Which is at the bottom of the spec. I guess this is a lesson on where are your fastners are manufactured. I will be calling to find out where they were obtained. I have replaced them with some USA Grade 8 bolts. I will also test the Grade 8 bolts for there Rc.:coffee