So let me get this straight.

Discussion in 'Motorized Bicycle General Discussion' started by Finfan, Sep 14, 2008.

  1. Finfan

    Finfan New Member

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    I'm sitting here with a new bicycle and an engine kit. The bike has a coaster brake. I apparently have the option of either enlarging the hole in the sprocket or finding a bench grinder and modifying the dust cap. Am I correct on that? So, if I get one or the other done how do I get the sprocket on over the coaster arm? My largest hammer is 3 lbs but I do have an 8 lb chopping maul that I could use as a sledge. :rolleyes: Any advice on how to approach this would be appreciated! There seems to be very little information posted on exactly how to fit the sprocket to the wheel. Please use small words and pictures!
     
  2. deacon

    deacon minor bike philosopher

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    You have to remove the BRAKE ARM in order to fit the sprocket on the wheel. Just a nut holds it on. No big deal but then you have to put a bend in the ARM so it clears the bolt heads of the sprocket. There is a picture of that somewhere here. Someone probably knows where it is I don't right off hand. After the sprocket is on just reverse the steps and you have it.
     
    #2 deacon, Sep 14, 2008
    Last edited by a moderator: Sep 14, 2008
  3. mgladden2

    mgladden2 New Member

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    Dig around on the spookytoothcycles.com website for the tutorials. You remove the coaster brake arm, mount the sprocket, then bend the coaster brake arm so it clears the bolt heads. I just took the arm and put a socket-set extension piece under it so it was lifted at an angle, then banged on it with a hammer until I had the right amount of bend. Took about 5 minutes. Mounting the sprocket on the wheel is harder because you need it to be very, very centered and evenly tightened to avoid it from wobbling at high speeds (makes the whole bike vibrate back and forth and you don't go as fast).

    Good luck!

    MG
     
  4. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    No hammer needed.
     
  5. Dave31

    Dave31 Moderator
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    Some brake arms need to be bent...some don't.

    On my last wheel I had to bend the arm...on my new wheel that I just got a few weeks ago I did not.

    I shaved a little off the mounting bolts on the sprocket to help clear the brake arm just to avoid buying more bolts.

    Some use flat head bolts, and some counter sink the bolts into the sprocket.

    Trimming the dust cover is a lot easier and faster then enlarging your sprocket center. The link in the previous thread will show you what need to be done.

    [​IMG]

    [​IMG]

    If some pics of my set-up will help...just let me know, I will be more then happy to post them. And if you really need help, we can make arrangements and I could stop by and give you a hand.
     
    #5 Dave31, Sep 14, 2008
    Last edited: Sep 14, 2008
  6. Finfan

    Finfan New Member

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    Thanks all! I did find the Spooky tooth page and I would like to inform FR31 that his dust cover mod can be accomplished with a vise, dremel, and file. However it doesn't really matter now because I decided to try out my new torque wrench and seal the head gasket. One of the head bolts stripped (inside the lower end) at 9 ft/lbs. I'm shut down for now. :(
     
  7. Finfan

    Finfan New Member

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    Having studied the matter further and read the thread about the stripped intake bolt I am going to try the JB weld fix using some new threaded stock unless somebody has a better idea. The JB weld that I have is in the Red and Black tubes. Is there a different type that would work better? I will overcome this! Onward through the fog! :bike2:
     
  8. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Did you strip a head stud, the nut for it, an intake stud, or the nut for IT?
    Or did ytou strip out the case or cylinder?
    I'm confused.
     
  9. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    You said head bolt, AND intake bolt....both?
     
  10. Finfan

    Finfan New Member

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    Joe:
    Sorry, my writing skills go down the tubes when I get aggravated. I was referring to another thread about an intake stud that stripped which gave me the idea for using JB weld. My problem is that the threads in the block appear to have stripped for one of the studs for the head. I should have known something was not right when the stud came out instead of the nut. Closer inspection has shown me that the nut is frozen to the stud. Probably cross threaded. Anyway there do appear to be some threads left in that I can turn the stud in but it wont take torque. So I am going to try the hillbilly fix and JB weld it in place. Do you think 8 ft/lbs will be adequate to hold the head? I'm nervous about torquing anything on this engine now.
     
  11. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Yes, I would find some "all thread" M6X1.0, and make a new stud, and JB Weld it in.
    If you want to use the old one, clean the remaining threads with some type of evaporative solvent, and JB weld the stud in place. Let it sit overnight before torquing down.
    8 lbs, should hold it it you torque everything evenly.
    The worst that will happen is the head gasket may leak a little, but a lot of these engine do leak some.
     
  12. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    What happens sometimes is the acorn head nut is already bottomed out, and if you try to torque it, it will pull the threads in the case. I remove the acorns and put a washer under them. Probably best to use a regular open nut.
     

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