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FXRS wobbles

Discussion in 'Motorcycle Tech Talk' started by fxrsrules, Nov 4, 2007.

  1. fxrsrules

    fxrsrules New Member

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    My fxrs has the wobbles. It's fine in a straight line to well over 100mph but when I hit the twisties it has a tendancy to wobble while haulin ass in both left and right turns. It's has 39 mm fxrs front end. It is a 86 frame and 90-94 drive train/front end, final chain drive. 100/90/19 front tire and 130/90/16 rear tire both Dunlop K-591. Iv'e tried a fxd front end and it wasn't much better. Iv'e had it aligned same same. It has done this forever but it seems to be a little worse after instaling a S+S 124 some years ago but now I'm finally had enouph and geting around to fixing it. Was wondering if the rear end is trying to pass the front end (to much power) or if the front end is flexing or somthin in that line. I know there are a lot of gimicks out there for this and don't want to waste time and money on snake oil. Thanks for any advice. :wtf:
  2. mwelych

    mwelych Active Member

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    You say you've tried working on the front end and never fixed it. How about looking at the bushings on the rear which holds the rear sway arm to the frame. Could they be worn??? Just an idear...:)
  3. fxrsrules

    fxrsrules New Member

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    yup...new.... yanked off my swing arm. even had harley presem in tossed it back on. same.
  4. fxdxriderleo

    fxdxriderleo Active Member

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    wobbles

    if you have been swappin parts i assume you adjusted everything properly, checked wheel true and balance then you may want to try a fork brace, it will remove the flex from you forks. a steering damper would help some. it would remove the faster wobbles .
  5. fxrsrules

    fxrsrules New Member

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    yea shure everything is adjusted properly and true. I got the duedad and the thingamajigie all in line and as tight as I could get it. Next was gona be the brace and or dampner. I was checking to see if I was missing the entire boat on something. Thanks
  6. cowboy

    cowboy Moderator Staff Member

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    Double check your tire presurer & try the fork brace , if it goes stright fine but wobbles in the corners , check the side of your tire's for bumps
  7. hotroadking

    hotroadking Super Moderator Staff Member

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    Have you replaced the front motor mount, as well as the stabilizer links.

    When you did the rear swingarm did they upgrade to the newer rubber isolaters, they have three rings and are stiffer.

    Get the mounts all replaced including the links and have the motor and swingarm properly and professionally aligned to the frame.

    The basics are the key

    The other options are to add a True Trak or Ride STR8 unit to the bike, it bolts under the trans to the frame and then to the swingarm to stabilize the side to side movement you are experiencing.

    In addition the 124 is putting out a lot more TQ which can create flex and if done at the wrong time in a curve spinning the wheel, Good new tires make a difference.

    I would suggest Avon Venom X for your style bike I run them on my Heritage and the turn in on curves is a major improvement over the Dunlop Square bottom HD tires. Run them on the front and back.
  8. fxrsrules

    fxrsrules New Member

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    Thanks for the combacks from all. Hotroadking.. I had it professsionally alined a few monts back. I could have swore I changed the front motor mount when I changed the links 13,920.01 miles ago but I have no record of the motor mounts just the links, thats good advice thanks. When I replaced the isolators I had them put in the super mamboe jamboes. I did try some metzlers (880 or somthin like that) same same. They were great when it was dry but as soon as it rained they had a tendancy to slip so I went back to the dunlop 551. Iv'e never tried the Avon how are they in the rain?? Another way to fix this is to just slow down a little to, but that would make to much scence. I just can't do that. I tried to contact tru-trak a while back so I could get one for my glide, but at the time all I got was a blank screen. .I'll try again. thanks again.
  9. fxrsrules

    fxrsrules New Member

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    fxrwobbles

    OK... swaped out the old front motor mount and put in the new updated and improved genuin harley mount. There us a big/huge improvment in the left corners but still have a problem with the rights. Also the bike is vibrating not alot but more than it was. more at low RPMs to aprox 1500 then it's smooth. It's not a sharp vibration like the motor hiting the frame but like the one my ole lady likes. I would go with that but it just aint right. any suggestions?
  10. mwelych

    mwelych Active Member

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    Just an idea since it popped into my head reading this over... How about loose spokes, iffn' ya have any???:)
  11. fxrsrules

    fxrsrules New Member

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    Nope.. Mags
  12. hotroadking

    hotroadking Super Moderator Staff Member

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    The mount allows it to move some, sounds to me like when you replaced the mount it may have corrected some alignment issues.

    How are the Heim joint alignment bolts are they in good shape?

    If they get old they get really stiff and can cause problems, just went through this on a 98 RK that shook like crazy and was a problem in corners like yours.

    Basically we replaced everything that connected the motor/trans to the frame and had it re-aligned.

    The other thing is to be sure the rear and front tires are in alignment and that you have a good tire on the back, low pressure and low tread will cause it to get out on you.

    Not saying you need to throw money at it but these are the things we ended up doing to correct a sway in the RK>
  13. fxrsrules

    fxrsrules New Member

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    Hotroadking.. I'm guessing here but I take it the the "heim aliignment bolt" are the bolts on the stablizer links? If not forgive me for being a little ignorant but what the hell is a heim bolt.
  14. hotroadking

    hotroadking Super Moderator Staff Member

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    Stablizer links they have swivel balls in the end, if they are old the rubber in the ends falls apart they become loose and allow some flex,

    We put new ones on the 98 RK and it really helped I guess what I'm saying is after a while we had to just bite the bullet and replace all the mounting points, joints, mounts and swingarm bits.

    Now the bike tracks straight and good in corners.
  15. harleydave51

    harleydave51 New Member

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    Hmmmm, I find this very interesting because I'm having the same wobble on my FXRS. I'm thinking about changing the swing arm bushing first and going from there. Thanks for all the ideas. Oh , and mine is an 89 mostly stock. Dave
  16. fxrsrules

    fxrsrules New Member

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    Welcome to the hood harleydave51 there is a lot of people that have forgot more than I will ever know about bikes here you are in a good place.. If and or when you come up with a remady let me know what it is, I would sure apreaciate it. I'm still having vibration problems with this thing (it's ruling my life again just like my name here). If I put the old mount in it's fine but it wobbles more in the corners. With the new and improved mount it vibrates more I'm sure it's partly because of the rubber is a little more stiff or dence than the old one. anybody got any more ideas?
  17. CD

    CD Guest

    Had a little experience with FXR's ;) over the years. As far as I know there was never a stock FXR frame that had any flexy flier problems. The wobbles on rubber mounts that are not wheel / tire (spokes, axles, bearings) or steering head bearings / worn forks tube bushings related are almost always caused by the drive train alignment, condition of the stablizers, front mount and the swingarm doughnuts and bushings. Many shops will claim to know how to align an FXR / FL drive line but in reality don't.

    You have to remember that the entire drive line including the rear wheel are a single unit and not attached to the frame but float on rubber mounts. I have seen rubber doughnuts installed incorrectly, busted engine mounts, trashed bushings etc, etc.....but even with all new parts if the drive train is not aligned properly you can get wobbles in turns and an unsettled feeling in straight line tracking.

    If the rear tire is not in line with the front, the handling is effected a bunch. Let's say the leading edge of the rear tire is pointed to the left side of the bike a little. When you go into a right hand turn the rear tire is going to try and cut a larger arc than the front because it is not in the same plane. The rear will keep trying to swing out and you have to constantly correct it. in a left hand turn the opposite is true but it will be more stable since the rear wants to go into the turn more but weight and side forces make it much more negligible.

    If you have no woobles in straight line riding and only in one direction of turn I would put my pennies on drive train alignment.

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