Total bummer - Broken engine mounting stud

Discussion in 'General Questions' started by Standard Issue, Mar 24, 2007.

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  1. What a drag!

    I'm out on my motored bike, havin a freewheeling good time when
    all of the sudden, I feel the motor give way and start to vibrate in
    an alarming fashion. Upon inspection, it turned out that the long stud
    in the rear had broken off. I found it on the road, and wouldn't you
    know it, it broke in about the worst place it could have, right about
    1 millimeter below flush on the casting.

    So I took the whole thine apart, drilled it and extracted the stud with
    an EZ-out. Fortunately that went smoothly.

    Now to find some replacement studs, and I'll be back in business.

    I have to say, I am a little dissapointed that a stud broke off after only
    about 5-6 hours of runtime. Not too broke up about it is just
    a cheap chinese bike engine. I expect a little bit of crappyness...kind of
    comes with the territory.

    Has anyone else had a similar problem, and if so, where were you
    able to locally procure some replacements?

    standard issue

  2. RLK

    RLK Guest

    I don't know exactly what you are talking about, but I know that the local ACE Hardware always has any and all metric threaded hardware i've ever needed. Go easy with the wrench, don't torque that cheap Chineese junk too tightly. Loc-tite everything! Vibrations will shake everything lose but if you go too tight you end up with broken bolts. Loc-Tite is your friend.

    To all the other hardware stores besides ACE that do not carry anything Metric I say, "Go pound sand, mu^&^$@#@($"!!
  3. Thejman

    Thejman Guest

    samething happened to me in the first hour was a big bummer.

    Had to order screws from

    but later went to theisens and they have 6mm studs but its a bolt, works good none the less.
  4. ibeenjammin

    ibeenjammin Guest

    This just happened to me on my way to work! I was about 2 miles from work with nothing but hill in front of me. I herd a loud pop, then the motor starting shaking violently. :shock: I immediately stopped on the side of the road, shut the motor off and noticed that I lost one of the mounting studs on the back where the bracket attaches to the seat post part of the frame. I was able to use the motor sparingly as I peddled the rest of the way to work. Thank goodness for peddles. I can't tell how bad the damage is. I don't know if it snapped off or if it stripped the threads and destroyed the casting. I will find out soon enough. The Mrs. has to come and pick me up from work. What a drag.
    Last edited by a moderator: Dec 15, 2015
  5. azbill

    azbill Active Member

    been there, done that :x
    a valuable lesson tho, I check they are tight now before every ride
  6. gone_fishin

    gone_fishin Guest

    the 10mm combination wrench is your best friend!!

    always carry a 10mm wrench, & check mounts, intake, & exhaust every day, especially if you're a commuter 8)
  7. ibeenjammin

    ibeenjammin Guest

    I already carry every tool I could possibly need. Or at least so I thought until the motor mount bolt snapped off in the motor. I never thought I needed to carry a screw extractor with my bag of tools.... :sad: Crap! I am not sure if that will even work yet, because I still haven't had an opportunity to asses the damage. I will keep you all updated.
  8. gone_fishin

    gone_fishin Guest

    wasn't trying to rub it in, sorry it looked that way :???: 2.5k miles and still using same studs/nylocks/no locktite but i'm obsessive about checking everything.

    anyway, there's been some good luck around here extracting the studs, so i'll cross my fingers for a good repair, let us know 8)
  9. azbill

    azbill Active Member

    when mine broke, it was flush with engine
    I used a dremel to cut a slot in the stud and used a screwdriver to extract it
  10. ibeenjammin

    ibeenjammin Guest

    Smart man :cool: Way to use your head.....obviously not just a hat rack. :D :D :D

    Hopefully mine is close enough to the casting that I could do that as well. From first glance, it looks like the whole thing ripped out threads and all. Unfortunatley, I am at work and I haven't been able to get a good look to see how bad it is. Thanks for the tip though :D :D :D

    The fun continues...after removing the motor from the bike, the bolt snapped off with part of the bolt flush with the casting, and the other portion below the casting. I tried cutting a notch in the bolt and use a screwdriver to get it out, but couldn't cut a deep enough notch. So, after getting very frustrated, I pulled out the drill and started with a small bit and worked diligently with a screw exctractor bit which did nothing but put a nice shiny counter sink mark on the bolt. Arghh :x :x Kept going up in drill bit size and working the screw extractor and stripped about a good 1/4 in of the threads going into the motor. I thought I was going to have to pull out a tap and re-thread the sucker. There was enough thread to still securely attach the motor back on. After securing the motor, I added the screw just above the motor mounts (Which barely fit infront and in back) that typically attach the water bottle cages and to my surprise it has made a significant improvement in reducing the amount of vibration from the motor. This may sound dumb but the bike feels more solid. I will post a pic when I get a chance if anyone is intersted.

    Thanks for all the help! :grin: :grin:
  11. One of my lower mounting bolts broke off the other day. It was still ridable but made a little more noise. I didnt have a clue how to fix it so I got some baling wire and tried to secure the engine to my bike frame. I rode it to work today and didnt have any problems.

    On a side note I'm leaking a very small amount of fuel between the shutoff valve and the gas tank. Instead of ordering another gasket I'm trying out some duct tape and welder contact adhesive. I tried just the welder stuff but it mixed with the fuel and didnt hold.
  12. turbo/chaos

    turbo/chaos Guest

    i never use any of the stock bolts i go to the hardware store and pick up grade 5 m6 bolts that are construction tuff
  13. I replaced all my bolts and studs with grade 5 allen bolts before even mounting the motor. Thought better safe than sorry after reading alot of posts on here. Also never like the grip a screwdriver gives you on the stock bolts on these engines or Japanese engines from my motocross days...
  14. Bikertypeguy

    Bikertypeguy New Member

    I broke one off and had to use an ease out to get it too. I just got a long metric bolt and ran a nut up close to the head of the bolt. I threaded the bolt through the mount and ran it in a good ways. Then I just put a wrench on the head of the bolt and ran the nut down with another wrench. Got lots of miles on it like that.
  15. jared3377

    jared3377 Member

    Shearing engine-mount bolts

    I've been shearing a bolt on my front motor-mount, too. I'm not sure exactly what to do yet (besides replacing them and even carrying a spare). I also went with grade 8 bolts from the local hardware store, which I was told was the highest. I've just been taking it a little easier lately, babying her a little.;)
  16. Marktur

    Marktur Member

    What length bolts?


    PS. Email me your answer so I can see it on my Blackberry...

    Thanks friend!
  17. kjparker

    kjparker Member

    what? you cant surf the forums on your Blackberry? Time to upgrade I think! :)