fork dependant speed wobble ?

[6m459]

Hi,

 

I have two sets of forks for my 84 xvz12, both sets have progressive springs in them.

 

One pair came with the bike at 20,000 miles and the other I bought on ebay because I couldn't get any life out of my fork seals on the originals. I surmised that rough spots on the forks were tearing up the seals even though I had done my best to smooth them out with judicious use of a fine stone and lots of oil. I wish I had tried replacing the bushings too but never did that.

 

All in all I'd say that the ebay set are in better shape and do have new bushings, but the original set are not too bad except for the fork seal issue.

 

With the original set the bike rides true and steady. With the replacement set, I get a wobble if I take my hands off the bars. No wobble is apparent till I take my hands off the bars and the bike rides well so long as there are hands on.

 

I don't understand how substituting forks can cause this sort of thing. I don't have any fancy instrumentation to check but the troublesome forks don't look bent or deformed in any way and as I say they are in marginally better shape than the original pair of forks.

 

Any one have any suggestions or insights into how to trouble shoot this ?

 

Thanks,

 

Brian H.

[bobcat]

I always equate a front end shimmy with the steering head bearing...that has always been the case with me...

It seems odd you'd get a wobble with one set of forks and not the other but I'd still tighten the steering head bearing if for no other reason then to eliminate it as the potential problem.....

[trickytom]

I had the same problem with my other 83 XVZ 1200. I changed tires, because I needed a new set and had them balanced, no more problem. When I would take my hands off before big wobble, after tire change and balance what a difference.

Tricky Tom

 

Hi,

 

I have two sets of forks for my 84 xvz12, both sets have progressive springs in them.

 

One pair came with the bike at 20,000 miles and the other I bought on ebay because I couldn't get any life out of my fork seals on the originals. I surmised that rough spots on the forks were tearing up the seals even though I had done my best to smooth them out with judicious use of a fine stone and lots of oil. I wish I had tried replacing the bushings too but never did that.

 

All in all I'd say that the ebay set are in better shape and do have new bushings, but the original set are not too bad except for the fork seal issue.

 

With the original set the bike rides true and steady. With the replacement set, I get a wobble if I take my hands off the bars. No wobble is apparent till I take my hands off the bars and the bike rides well so long as there are hands on.

 

I don't understand how substituting forks can cause this sort of thing. I don't have any fancy instrumentation to check but the troublesome forks don't look bent or deformed in any way and as I say they are in marginally better shape than the original pair of forks.

 

Any one have any suggestions or insights into how to trouble shoot this ?

 

Thanks,

 

Brian H.

[mother]

did fork brace, still shimmy

changed front tire, still shimmy

replaced steering head bearings, and voila, shimmy gone. the bottom bearing showed wear, the top one looked good, but i replaced both. the steering head has to be snug, not tightened down. if steering head is loose, shimmy will occur also.

cheers, Scott