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  • Spring fork problems

    I finally got my '48 Big Twin together and on the road last year(I thought it would be better discussion in Knuck section) and have been riding it for a year. I've owned and have been riding/wrenching on Pans for 40+ years but never had a springer. In the last few days while testing the front brake I realized the spring fork was hardly moving. I was riding with a couple '46 Knucks and after holding their front brake and bouncing the front end it showed quite a bit of travel. After closer inspection I believe I installed the spring fork backwards. The casting numbers are facing the rear, and my buddies are facing the front. It seems that the bottom of the spring fork legs have a slight radius only on the front to clear the rocker. Mine seems to be backwards and binds at the lower spring fork leg to the rocker. I do have a Palmer, service manual, and spare parts book and I vaguely remember reading years ago about proper orientation when installing the spring fork leg, but haven't found it yet. Can anyone please enlighten me! Am I on the right track? The springer was a swap meet purchase 20+ years ago ($300.00) so it might be questionable, but it measures up correctly to a few buddies offset springers. Our own Don Dzurick had it on his table to check straightness years ago and he did not see anything out of line.

    Thank in advance for your thoughts and expertise.

    Kurly

  • #2
    Originally posted by kurly View Post
    I finally got my '48 Big Twin together and on the road last year(I thought it would be better discussion in Knuck section) and have been riding it for a year. I've owned and have been riding/wrenching on Pans for 40+ years but never had a springer. In the last few days while testing the front brake I realized the spring fork was hardly moving. I was riding with a couple '46 Knucks and after holding their front brake and bouncing the front end it showed quite a bit of travel. After closer inspection I believe I installed the spring fork backwards. The casting numbers are facing the rear, and my buddies are facing the front. It seems that the bottom of the spring fork legs have a slight radius only on the front to clear the rocker. Mine seems to be backwards and binds at the lower spring fork leg to the rocker. I do have a Palmer, service manual, and spare parts book and I vaguely remember reading years ago about proper orientation when installing the spring fork leg, but haven't found it yet. Can anyone please enlighten me! Am I on the right track? The springer was a swap meet purchase 20+ years ago ($300.00) so it might be questionable, but it measures up correctly to a few buddies offset springers. Our own Don Dzurick had it on his table to check straightness years ago and he did not see anything out of line.

    Thank in advance for your thoughts and expertise.

    Kurly
    Your front leg is facing the right way. Every original springer bike I have ever seen has the numbers to the rear. Your buddies are wrong. Something has to be bent if it is binding. Pictures sure would help.

    Jerry

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    • #3
      Kurly Are you sure you have the correct front leg. If you are running an offset fork as would have been stock on 1948 UL you would need a #15 or #16 with a milled slot or a #17, #18, #19 or a #20 front leg or the possibility exists that bridge of the rigid fork would interfere with the bridge of the front spring fork. A #18 would probably be the original for your bike.

      Jerry

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      • #4
        Thanks for the reply Jerry, here are some photos of the binding, as I can see. The "rocker plate stud nut lock" was installed upside down which was bent by the interference. I reread the service manual a couple of times and will check for fork crown not milled and any interference on the top. I was focusing on the rockers. I'm not sure if they are the correct rockers since I bought them at a swap meet all together. I took the rockers off before checking the top of the spring fork for interference.
        Attached Files

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        • #6
          The left rocker looks to be the pre-1941 style without the raised grease connection bosses, but they are not the 1930 rockers with a slightly different shape, so should not be the problem. Remember the spring rod bushings also changed for 1948, so worth checking.
          Last edited by Steve Slocombe; 04-17-2023, 03:47 AM.

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          • #7
            Thanks Steve and Jerry,

            I did get different spring rod bushings back in the day??? Its been over 20 years collecting some parts and I don't remember the details. I will reassemble the rockers without the shock and headlight to check clearance on the bridge, and have the nut lock on correctly. 82* Saturday & 31* with snow today, good shop day.

            Kurly

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            • #8
              Is the shock OEM or aftermarket? Some aftermarket are junk and don't move causing brackets to break. Also make sure your studs are long enough to not bind the rockers when tightened.
              Robbie Knight Amca #2736

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              • #9
                Success... Thanks all!

                It was my stupid mistake of installing the "rocker plate stud nut lock" upside down. I used locktight and did not try to bend the tabs to lock the nut. This caused the rocker to jam into the lower spring fork and prevent movement. I feel really stupid, but relieved it was a simple fix. I checked with feeler gauges and a caliper to insure clearance between the spring fork and the steering damper as I compressed the springs with a furniture clamp, thanks Jerry. I now realize I have one early rocker thanks Steve! I exercised the front end after measuring and correctly reinstalling the nut lock, and it has normal movement. Now to put the fender, shock, headlight and horn back on. I hope to see you on the 75th Anniversary Pan Ride and Celebration and at the HD Museum for the Wild Ones Weekend. Please stop and say hello if you see me! It should ride even better with spring movement..Ha Ha

                Kurly 1948 harley scetch.jpg

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