Clunking front end on my Sporty...

Discussion in 'Sportster Models' started by W1ld Card, Mar 14, 2011.

  1. W1ld Card

    W1ld Card Member

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    Alright, I apologize if I'm flooding the boards lately, I'm just trying to get my bike up to par for riding. It's definitely got an "unknown" history. All that I do know is that the bike fell while in storage at the repo-company.

    I've fixed up what I can, and I am waiting to re-align the front forks, as they're twisted very slightly in the triple-tree clamps.

    I was riding it tonight to the gas station to put some air in the tires, and couldn't help but notice a regular clunking sound coming from the front end.

    As I drove faster, the frequency of clunking would increase...not related to the RPM, but to the speed of the wheel. It was annoying, but I couldn't actually "feel" anything wrong in the handlebars.

    It didn't clunk on bumps, just whenever the front wheel spins......

    Am I missing something obvious here?

    Doug
     
  2. W1ld Card

    W1ld Card Member

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    Alright, it sounds like another project to do at my father-in-law's. I used to have tools....well, then I got married! :D

    Thanks for the tip, I'll bring my manual and check it out. Along with using an impact to loosen the triple-tree clamp pinch bolts.

    Doug
     
  3. Jack Klarich

    Jack Klarich Expert Member

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    Check the Fall away adjustment and check the fork oil maybe change it?
     
  4. W1ld Card

    W1ld Card Member

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    Alright, sounds like I'll have my hands full a bit! If the steering stem were loose, wouldn't I "feel" that clunking in my hands? I can definitely hear it, but can't feel anything...it's like a small "thunk, thunk, thunk..." as I ride down the road, at about 20 mph, it happens about 2 times per second. Maybe the wheel bearing could be bad, too, huh? I can barely hear it over the pipes.

    Oh, the fun of getting a repo...at least I got it for (hopefully) semi-cheap!


    Thanks for the input, fellas. Maybe one day I can contribute some answers to this board for a change!

    Doug
     
  5. Jack Klarich

    Jack Klarich Expert Member

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    Your turn will come as you find and solve your problems you will help others, and yes it could be the bearings or the brake pads or caliper, might as well check them too for peace of mind, and welcome to the Forum
     
  6. BUBBIE

    BUBBIE Well-Known Member

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    IF the thumping is SPEED related it could be a bad tire.. The frequency of the thumping Increases as the speed increases (tire move around faster)..
    Also a LUMP May be Seen or Felt on the tire.. Bet you I'm right......

    signed....BUBBIE
     
  7. Hoople

    Hoople Account Removed

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    Isn't it the other way around. If the neck bearings are set up tight, fall away number will be larger.
     
  8. W1ld Card

    W1ld Card Member

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    According to my shop manual, Hoople is right. Tighter head-bearings equal a larger fall-away.

    And Bubbie, you might be on to something. The bike only has 6000 miles on it, but it was in storage for at least a year. And, when I got it, the tire pressure was only 20 PSI on both tires (the manual recommends 30 PSI for the front and 36 PSI for the rear). Now that I think about it, it didn't seem to be thunking on the way to the gas station. But, after I filled the tires up and headed home, that's when I noticed it.

    Oh, the joys of bringing a neglected Harley back into reliable condition!

    Thanks for everyone's input, you guys really are great!

    Doug

    So, if it is a flat spot, is this something I should be worried about? It's not large enough to even really feel while riding.

    I was reading on another forum that some people will "over-inflate" the tires about 20% for about 24 hours to help get rid of the flat spot. Of course, they don't ride on the bike while the tires are over-inflated. Then, after 24 hours, they bump it back down to maximum inflation. After that, they'll ride it and see if the flat spot is gone. If it's not quite gone, the maximum inflation, the centripetal force, and the heat from riding will supposedly help the tire round itself out. Once the flat spot is gone, then they'll adjust the tire pressure back to where it should be.

    My bikes tires are both rated for 42 PSI max. Is this something I can try? That is, if this is a flat spot? I sit here, typing this from work, which is about 40 miles from my home. I'll definitely be able to inspect it better tonight, and get back to you guys.

    These tires still "look" to be in good shape, nice tread, no cracks or wrinkles, and no slow leaks. So, I REALLY don't want to have to get a new tire if I don't have to.

    Doug
     
    Last edited by a moderator: Mar 15, 2011
  9. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    It could be as simple as a small stone that has got stuck in the tread of the front tyre
    might be best to get the front wheel off the ground and give it a good spin the problem may reveal its self

    Brian
     
  10. W1ld Card

    W1ld Card Member

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    Well, after looking everything over and making sure there was nothing obvious making the nice, I decided to take the bike out on a 10 mile cruise. Most of the time was spent at 55-60mph.

    About a mile in, the thump was still there when I slowed down at a stop sign. I can't hear it when I'm going fast, only slower. But, at about mile 8, I stopped for an intersection, and it was gone. The rest of the way home, it was quiet, too.

    So, Bubbie was right. Seems as if it was just a little flat spot on the front tire. I didn't even bother over-inflating or anything. I just used the recommended air pressure and drove the thing. Good thing I didn't take him up on his bet :p

    Also, wow! First time I've ridden a motorcycle with no windshield! That wind really beats you, doesn't it?! My helmet felt like it wanted to strangle me when I was driving into a headwind (it's a half-helmet). I might just install the small front visor that came on it, that might add some "downforce" to the front of the helmet at speed.

    Doug