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  1. #1

    Default Bad front end wobble

    1978 HD FLH. Rides smooth as silk as long as you hold on to the handlebars. If you let go, good luck! The wobble will kill you. Is this as simple as a poorly balanced tire? Wouldn't you feel that when holding on like a car? Everything felt tight in the front end with front tire between my legs pulling and yanking. I will start with a balance but curious on any other similar experience out there.

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    Not a poorly balanced tire, but a bad tire. A good tire with no balance won't do that, but may cause some vibration. A bad tire, meaning the carcass of the tire is damaged or coming apart, will cause this. That is the first consideration.

    Next, loose spokes front or rear. That is not usually a problem on '70s bikes, but is or was a chronic problem on '90s H-D.

    Next would be wheel bearings and swingarm bearings. If any are bad front or rear, you can have handling issues as a result.

    Next, as you noted, something loose in the front forks. I have seen a late model fork with BOTH pinch bolts broken off. Don't ask me how, no accident or anything else to account for it.

    Next, bad steering head bearings, or steering head bearings out of adjustment, but that usually does not cause a violent wobble.

    Jim

  3. #3

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    Quote Originally Posted by JBinNC View Post
    Not a poorly balanced tire, but a bad tire. A good tire with no balance won't do that, but may cause some vibration. A bad tire, meaning the carcass of the tire is damaged or coming apart, will cause this. That is the first consideration.

    Next, loose spokes front or rear. That is not usually a problem on '70s bikes, but is or was a chronic problem on '90s H-D.

    Next would be wheel bearings and swingarm bearings. If any are bad front or rear, you can have handling issues as a result.

    Next, as you noted, something loose in the front forks. I have seen a late model fork with BOTH pinch bolts broken off. Don't ask me how, no accident or anything else to account for it.

    Next, bad steering head bearings, or steering head bearings out of adjustment, but that usually does not cause a violent wobble.

    Jim
    Thanks Jim.
    Great reply. Pretty new tire with little miles on it but will have it checked out. Also ordered new wheel bearings and will replace regardless when I get the tire checked and balanced. Then I will see if any better and move down your checklist.

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    I have had new tires with bad run-out. Must have come out of the mold that way.
    Also have had a neck that needed a 1/8 turn of a wrench to cure a wobble.

    Jim is right about spoke wheels. Dont just tighten the spokes, check for run-out.
    If all that fails to fix it then bearings are the obvious next step.

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    Might be worth checking they seated the tire on the rim properly when it was changed, if it was done recently.
    It's more likely to be what Jim said.

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    Don't overlook what Jim said about swingarm bearings. Looseness at the swingarm can feel like a front end wobble while riding. Using a lift or a jack under the frame get the rear wheel off the ground then try to move it side to side. Pull and push hard. Any discernable movement at all is bad.

    To fix it, strip it to the swingarm, check the bearings. and clean or replace them as necessary. To adjust them properly you need a small fish scale or postage scale that you hang whatever you're weighing from. Use it to weigh the swingarm at the very end when it's moving freely, then tighten the pivot bolt until it takes 1 or 2 pounds more to pull it up to straight. Example, if the end of the swingarm weighs 4 lbs., tighten until it takes 5-6 lbs. to pull it up.
    Last edited by MOTher; 01-24-2021 at 4:10 PM.

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    I had something similar in the forks. You notice it worst in a full lock, low speed turn. But it was kinda "there" all the time. I was scared to take my hands off the grips. It was that much.

    This condition survived two sets of wheels, tires, swingarm bearings, a swingarm pivot bolt, front wheel bearings, rear wheel bearings, neck bearings and finally only changed behavior when I changed the fork oil.

    I think one was empty, or pretty much, and probably very worn.

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    Quote Originally Posted by Canine View Post
    Pretty new tire with little miles on it
    Sometimes if you switch out only one tire, it will amplify the effect of worn components. I wouldn't ride the bike until you got it sorted out.

  9. #9

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    Quote Originally Posted by MOTher View Post
    Don't overlook what Jim said about swingarm bearings. Looseness at the swingarm can feel like a front end wobble while riding. Using a lift or a jack under the frame get the rear wheel off the ground then try to move it side to side. Pull and push hard. Any discernable movement at all is bad.

    To fix it, strip it to the swingarm, check the bearings. and clean or replace them as necessary. To adjust them properly you need a small fish scale or postage scale that you hang whatever you're weighing from. Use it to weigh the swingarm at the very end when it's moving freely, then tighten the pivot bolt until it takes 1 or 2 pounds more to pull it up to straight. Example, if the end of the swingarm weighs 4 lbs., tighten until it takes 5-6 lbs. to pull it up.
    I will try this out this weekend.
    There is zero wobble when riding, only when you take your hands off the bars

  10. #10

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    Quote Originally Posted by Fetch View Post
    Sometimes if you switch out only one tire, it will amplify the effect of worn components. I wouldn't ride the bike until you got it sorted out.
    No worries, I have 2.

  11. #11

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    Quote Originally Posted by confab View Post
    I had something similar in the forks. You notice it worst in a full lock, low speed turn. But it was kinda "there" all the time. I was scared to take my hands off the grips. It was that much.

    This condition survived two sets of wheels, tires, swingarm bearings, a swingarm pivot bolt, front wheel bearings, rear wheel bearings, neck bearings and finally only changed behavior when I changed the fork oil.

    I think one was empty, or pretty much, and probably very worn.
    Wow, this is something I would not have thought of.
    Adding to the checklist.

    All feels fine, riding and turning, just dont let go of the bars!

  12. #12

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    Quote Originally Posted by Tater66 View Post
    I have had new tires with bad run-out. Must have come out of the mold that way.
    Also have had a neck that needed a 1/8 turn of a wrench to cure a wobble.

    Jim is right about spoke wheels. Dont just tighten the spokes, check for run-out.
    If all that fails to fix it then bearings are the obvious next step.

    Tire has been on bike for a while, just little miles as some of its life was when top end rebuild was going on. No issue prior, and no remount since.
    Definitely will check the spokes, that is a possibly point of issue.

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