First bike build with coaster brake! HELP!

Discussion in 'Introduce Yourself' started by tmearce, Oct 27, 2010.

  1. tmearce

    tmearce New Member

    Hey guys
    I'm new to the forum but I feel like this is the best place to get real answers.
    I just got my 80cc engin e and I'm stuck on the rear sprocket assembly with the coaster brake. Do I need to have the dust cover practically attached to the sprocket? Or should it move freely??
    Thanks for any help!

    TrevDawg
     

  2. Al.Fisherman

    Al.Fisherman Active Member

    I enlarge the hole in the sprocket so the cap will fit. This does two things... Keeps cap intact and centers the sprocket. Others either cut the flange off the cap or discard the dust cap. Think...why is the dust cap installed to begin with?

    http://www.youtube.com/watch?v=M3IPgvZLccI
     
    Last edited: Oct 27, 2010
  3. tmearce

    tmearce New Member

    So your saying thaT I should be able to fit the dust cap throuugh the sprocket hole?
     
  4. Hammond Egger

    Hammond Egger Member

    It sounds like you are at about the same place with your build as I am. Yes...the dust cap should fit through the sprocket hole but a drill press is kinda overkill. just use a dremel tool if you have one and if not just use a half round file.
     
  5. tmearce

    tmearce New Member

    yeah im going to bust the dremel out and grind the sprocket down so i dont loose the dust cap. have you heard of put a freewheel onto a cruiser? the measurements are off but it would be a heck of a lot easier.
     
  6. Al.Fisherman

    Al.Fisherman Active Member

    A drill press is not overkill. With a drill press I can take the same amount of material off all the way around, thus the sprocket will self center when placed over the cap perfectly and look professionally. A drill press is the way to go, but if unable to access a drill press then a dermal too can be used, although not as accurate.
     
  7. Hammond Egger

    Hammond Egger Member

    I can draw file to within .010 to a line and that's closer than any dust cap I've seen is round. My daddy told me never to use a drill press for a rotary file; he said they were neither designed or intended for it; especially the homeowner versions. Something about side thrust not only damaging the quill bushing but that it was also a safety issue. He also said never to use a vernier caliper for a scribe....especially if it belonged to someone else.
     
  8. Stan4d

    Stan4d Banned

    I think I missed something. I did not see the post saying to use a rotary file in a drill press. Using a drill press is the way to go, provided you use it for what it is intended for. Hole saws and not rotary files.
     
  9. Hammond Egger

    Hammond Egger Member

    Methinks you missed the youtube video. I just modified a sprocket with a half round file; you only have to take about 1mm off. As far as accuracy goes it's within about .005
    We're not building a piano here.
     
  10. Stan4d

    Stan4d Banned

    Your right. I missed the video, but he is using it as a press. I took it to mean that the bit was dropped down and the sprocket was pressing against it lateraly. I still preferr the hole saw. No its not a piano, but some put the same effort into the build. (Nothing wrong or right about it, just different ways to "skin the cat")

    Also, as far as only 1mm removed, remember that different sprockets have different sized holes, and the number of different wheels that are delt with.
     
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