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  1. #1

    Default Ironhead chopper neck cups

    So picked up this basket case ironhead, I noticed that they didnít have the neck cups installed. They were just sitting there. So Iíve been attempting to install them and for the life of me cannot figure it out. Iíve uploaded a picture of my neck to see if maybe Iím doing something wrong? Is it possible to not run the cups and find a bearing that will work? It seems like the cup and the shaft are the same diameter.
    Attached Thumbnails Attached Thumbnails BAB73F54-48F2-48A4-BA51-D47F441123CD.jpg  

  2. #2

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    Ironheads use a smaller stem and smaller bearings. You might have big twin bearing cups, which are too big.

  3. #3

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    Ironheads use a 7/8" steering stem and the bearings and cups are thus smaller than on a Big Twin, which has a 1" neck stem.
    There are conversion bearings and cups out there to run a Big Twin front end on an Ironhead, if that's something you're trying to do.

  4. #4
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    Conversion cups also permit later Sporty front ends like the 39mm which can be had with decent brakes if you like stopping. Since you're in there anyway I'd run those unless you want a stock front end because they give you far more custom options. You can get the inner race and cage to fit whatever.

    Timken-style bearings are sold by inner race with caged rollers and corresponding outer races to offer more ID/OD combinations with fewer part numbers.

  5. #5

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    I had a buddy that works at a dealership order me neck cups for a 75 which I believe is what my frame is. The cups that came in measure the same as the ones I have. Which measure 1 1/4 at the stem and won’t fit in my neck

  6. #6

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    You do realize that the cups are a press fit? Two or three thou press, unless the frame is stretched. You will need to drive them in, or draw them in with a tool made for the purpose.

    Jim

  7. #7

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    Everywhere I read said it is possible with a hammer and wood or a threaded rod with washers but it won’t even get started

  8. #8

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    All the K and XL frames had the same ball bearing cups from '52 to '78 I think, and the' 79 and '80, and maybe '81 had a Timken set that fit in the frame the same way. If your buddy ordered cups for a '75 frame, and you have ANY one of the small stem XL frames, the cups should fit. (Your pic does seem to show a small stem XL frame.)

    You need to do some accurate measuring.

    Jim

  9. #9
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    Clean that neck up and get us a good pic. What I'm seeing doesn't look like a machined recess. Looks more like a ball race for something.
    Dusty

  10. #10

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    Quote Originally Posted by DustyDave View Post
    Clean that neck up and get us a good pic. What I'm seeing doesn't look like a machined recess. Looks more like a ball race for something.
    Dusty
    Looks like a typical bored XL steering head with a chamfer to me.

    Jim

  11. #11

  12. #12

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    Bump

  13. #13

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    You have bearing races in there? That's what the 2nd picture looks like. Get them out. Cut them carefully, or try tapping them out from the opposite side.

  14. #14

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    Quote Originally Posted by Down View Post
    You have bearing races in there? That's what the 2nd picture looks like. Get them out. Cut them carefully, or try tapping them out from the opposite side.
    It doesn’t seem to be a race. Looks like it’s part of the neck

  15. #15

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    Picture 2 is definitely not part of the neck. That's a race in there, where the neck cup should sit. That's why it won't go in.

    Wait for the experts to weigh in, this is just my opinion.

  16. #16

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    Quote Originally Posted by Down View Post
    Picture 2 is definitely not part of the neck. That's a race in there, where the neck cup should sit. That's why it won't go in.

    Wait for the experts to weigh in, this is just my opinion.
    Iím sorry the second picture is of the neck cup I have!

  17. #17
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    not a very accurate measurement with a carpenter tape measure...grab a digital vernier for that level of measurement:

    good enough for that...but not engine building:
    Click image for larger version. 

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    https://www.harborfreight.com/6-in-d...per-63711.html

  18. #18

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    The XL cups I have, have a shank OD of 1.189 - 1.194. In fractions that would be 1 3/16.

    Jim

  19. #19
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    Quote Originally Posted by JBinNC View Post
    The XL cups I have, have a shank OD of 1.189 - 1.194. In fractions that would be 1 3/16.

    Jim
    Thanks for that info.
    I have searched for it before, and again for this thread...found the BT cups spigot at 1.3125" to fit 1.310 neck bore ID.

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