Funny Oscillation

[h2olawyer]

If it's corrected, it could have been draining both forks & making sure they each had identical amounts of fluid.  It also may have been the readjustment of the fork brace.  I left the tire pressure @ 33F 36R.  I also had no extra weight - no luggage & no tank bag.  However, I didn't get up to the higher speeds & the curves weren't quite as sharp.  However, I was looking for the wallowing & @ 75, felt none.  I'm taking another test ride - back to North Park, where I first felt it - this week to see if it's really fixed.

H₂O

[Night Vision]

it might have just been a timespace continuum gremlin...

.....now that you're no longer in that timespace... the gremlin isn't either  ???

[h2olawyer]

I like that theory - best one yet!  Still, I won't know for sure until I try to replicate the conditions through North Park & have a chance to do some sweepers @ 80+.

H₂O

[jasonm.]

I have always had a slow wallow during the following combination ONLY....While in a sweeper on very steep down hill 85mph+. There are not too many roads around me that have this combo.ANd I don't often go over 85 for long periods. So I don't consider this an issue.  I think I my case it's just less weight on the rear.  These bikes don't have the stiffest frames in the world. But good for what they are.

[js9_20]

I know this is an old thread but, I've been experiencing the same  squirrely "oscillation", at high speeds mostly (75-85,) especially through sweepers.  I have noticed it when riding aggressively through tighter turns as well. 
I've been leaning toward swing arm bearings/bushings as the culprit but, decided to filter through the old posts before tearing it apart.

This thread seems to have died out without clues to resolution.

Basically, I'm experiencing exactly the same problem as described in this post and I'm wondering if any conclusive results were determined..? 

I doubt it's Time/Space Gremlins though, since it has been reoccurring for quite some time now.  :)

[QBS]

Check out the last few days of "the good..." on the General Board.  I've made some observations there that may apply to your situation.  They are related to steering head bearing failure diagnosis.

[js9_20]

Yeah, I did read through that thread recently but, I "think" my issue is not in the steering head.  There's certainly no resistance in the steering action at all.
However, I will double check that scenario too. 
Thanks for reminding me, I need to say hello to "Monster," since I live about 30 miles from Santa Cruz.

I did put cone/needle bearings in the steering head last summer but didn't notice the warble until the end of the year. 
...  It doesn't feel like it's coming from the front though.  It's much like the rain grooves feeling but, greatly exaggerated... and, not constant.

Its really quite uncomfortable when it kicks in at 80 mph but seems to dissipate at about 75 and under.  So far the best way to relieve the worble is to keep it under 75.  haha.  But, I know the problem is still there, all the time.

Thanks for your comment.

[Ken Williams]

I experienced weave in high speed sweepers on my bike.  It turned out the elastomer in the end bushings of my Fox shock had packed down.  This resulted in as much as an inch of undamped rear wheel motion.  To fix this problem, I replaced the stock bushings with automotive suspension bushings. 

[js9_20]

I see...  I will look into that as well.  I did however, recently replace the shock with a good used one.  I've experienced no change in the warble.  I didn't put new bushings in the shock so, it is possible to have a second set of bushings that are worn too...

Hmmm,   Maybe I should revert to using only new parts~  haha  what a concept!

Thanks

[NITROPOLIS]

I'm no expert, but while dismantling my '82 I discovered a bit of slop in the swing arm pivot point. I had the upper shock mount off and the rear wheel off. I could
grab the swing arm at the wheel mounting point and wiggle the swing arm side to side. More play than I thing it should have. Just a thought.

[js9_20]

Yeah, that's what the book recommends for checking swing-arm bearings/bushings. 
I'm planning to check out as soon as I have a chance to pull it apart.  Maybe this weekend, if not sooner.
Did you experience any handling characteristics prior to addressing the issue? ... Assuming you did address the "slop" issue.  Did the issue go away?

Thanks

[NITROPOLIS]

Never rode it enough to find out before dismantling. had a Concours and an '81 seca 750 to keep me busy. I bought the bike from a guy in south San Francisco, who got it from a lien sale. picked it up for $250 had the starter clutch issue. then when I went to register it the fees where over $750 bucks, so the bike sat
for a few years.

[Rikugun]

This thread seems to have died out without clues to resolution.

An oscillation like you described can haunt even the most knowledgeable suspension tuner.  :( I re-read through all the comments and they're all good suggestions. There are so many possible contributors its tough to pinpoint the cause for every bike. Every bike is a little different in it's setup and components and most importantly all riders are a little different. One thing not mentioned is often a big contributor - rider input. Depending on how the pegs are weighted for example, I can help or hurt an oscillation on my bike.

I had to work through an oscillation problem when I got this bike and tried most things mentioned i.e. tapered neck bearings, checked swingarm bearings, fork oil changes, new tires, new fork springs, experimented with fork mounted fairing/frame mounted fairing/no fairing, etc. All had some effect but I'd say the thing that really brought it all together was replacing the rear shock assembly. If you have the 82 shock on your bike, I don't imagine you'll ever resolve the oscillation problem.  :(  They are just dreadfull.  :'(

Given the very basic forks, dubious swingarm attachment points and a few other questionable aspects, I'm actually impressed with how well my bike handles now especially given where it started from - that being an ill handling, sphincter tensing, confidence robbing mess.  :D If you are persistent and spend some time and money you can get these bikes to handle fairly well. Just keep in mind it's old technology and don't expect too much!  ;)  :)

[Rick G]

CA. DMV is insane . Thats one reason I bailed on the "golden state" in '89/ Sell it in Nevada or Oregon and side step the insanity!

[js9_20]

Never rode it enough to find out before dismantling. had a Concours and an '81 seca 750 to keep me busy. I bought the bike from a guy in south San Francisco, who got it from a lien sale. picked it up for $250 had the starter clutch issue. then when I went to register it the fees where over $750 bucks, so the bike sat
for a few years.

...  Seems that the price is what gets many of us hooked.  Fortunately for me, mine had been sitting so long, the fees were no longer due, because they had no record of it.  :)

[js9_20]

Rickugun,

I have an 83 shock mounted on it (recent.)  Rebuilt the forks and new seals, last year.  Tires are in good shape (Shinko.) 
I think next move is to replace the fr and rr wheel bearings with the new ones I have and, check the swing arm for signs of wear, slop, etc. while the wheel is off.

Well, it shouldn't hurt the bike to keep replacing with new stuff, until the issue goes away... 
Hopefully, it will go away.

[js9_20]

CA. DMV is insane . Thats one reason I bailed on the "golden state" in '89/ Sell it in Nevada or Oregon and side step the insanity!

Its not for sale...  :)

[Rikugun]

Well, it shouldn't hurt the bike to keep replacing with new stuff, until the issue goes away... 
Hopefully, it will go away.

Agreed.  ;) Just the shock swap alone would not have gotten me there. The one thing I haven't been able to eliminate is the tank slapper that develops when I let go of the bars.  :(

[js9_20]

Oh!   :o   That's not good.

[QBS]

If all else fails, hold onto the handle bars.