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Old 06-11-2012, 05:49 PM   #31
backroadbob.com
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The Wobbles?

Before you do anything, check your wheels and wheel alignment. Almost no factory motorcycle has its wheels perfectly aligned and most, if ridden for any distance, have wheels bent beyond spec. Shaft drive bikes require computer laser alignment and the rack and jigs to align the front to the back wheel. Chain drive bikes can use tools like the old Hentner wheel aligner and use the chain adjuster to align the back wheel to the front wheel. Bent cast wheels require cold bending if you don't want to buy a replacement that's possibly worse than the one you have.
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Old 06-11-2012, 06:49 PM   #32
JonnyCash
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I'm glad to read this thread. My swb/5 will shake if I take my hands off the bars, and I always thought I must have something slightly off in the front end. It never does anything creepy, as long as I don't take my hands off the bars. My RD seems like you couldn't make it shake for anything, which I think is counterintuitive, as it is tiny and weighs about 290, and is much quicker steering. Thanks everybody.
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Old 06-11-2012, 07:40 PM   #33
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That's another thing funny about wobbles JC. Some people swear there airheads are rock solid. I have never been on a rock solid airhead and I have ridden a LOT of airheads. Your RD is. I have heard other people cuss a RD up and down for tank slapping. Sure a lot of it is setup, etc. but a lot of it isn't. A lot of it is how you ride. If you are a hard and fast rider, you can be as smooth as glass and still get into a tank slapper now and then. If you are a hard and fast rider and you are not smooth as glass. Lookout and invest in a real good steering damper! It's weird science. Rest assured that it isn't just your SWB that does that. There might be something wrong with it and there might not.
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Old 06-13-2012, 02:11 AM   #34
patanga OP
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Quote:
Originally Posted by ozmoses View Post
It was not a contentious query at all; quite the contrary.
My RS is only unstable at that exact speed range and after adjusting,readjusting sag,tire,tire pressure,blah,blah,blah I wonder why and, moreover, if it actually can be eliminated?
Hey ozmoses; Please forgive me if you already know the answer to what I'm about to ask; Re your RS; There's a lot of extra weight up front as you know. What is everything like condition wise?.. (Eg; forks, springs, fluid, head bearings, bearing adjustment etc etc).. I just tweaked the head bearings on my S faring R80 with the result = significant improvement.

Regards tyre pressures; I only run them up at 40psi as that is where I have got the best results on Battlax BT45's. I do enough varied condition riding and turns not to have the rear tyre suffer too greatly from the flat top syndrome.
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Old 06-13-2012, 05:05 AM   #35
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Patanga-

Tire is well w/in spec in terms of tread & air, fluid changed annually, forks in good repair. Head bearings have not/ do not seem to require adjustment so I haven't. But perhaps I should.

With the steering damper on "0" it is minimal, "1" or "2" really exacerbate it, oddly.

Springs-really this began when I replaced the originals w/ Progressive brand. The same exact spring which makes my /7 "rock-solid"!
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Old 06-13-2012, 06:12 AM   #36
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Quote:
Originally Posted by ozmoses View Post
Patanga-

Tire is well w/in spec in terms of tread & air, fluid changed annually, forks in good repair. Head bearings have not/ do not seem to require adjustment so I haven't. But perhaps I should.

With the steering damper on "0" it is minimal, "1" or "2" really exacerbate it, oddly.

Springs-really this began when I replaced the originals w/ Progressive brand. The same exact spring which makes my /7 "rock-solid"!
osmoses; Maybe the head bearings need a little tweak?.. I replaced a set on mine a few thousand K's ago and even though the steering felt ok, over time the bike developed the shakes. I knew the bearings had settled a little and adjusted them up slightly. It made a big difference. Obviously can't say with any certainty that's your fix but for what it's worth...

I used to see similar issues a lot on 4x4's with swivel hubs on solid axles.. As the bearings wear they develop small divets (due to the constant straight line hammering they receive) in the centre position. These marks obviously grow over time and the shakes get worse as well. What I suspect happens to a lot of airheads is that the bearings get replaced when they are trashed but the real damage started a long time before with lack of maintenance adjustment. The slightest mark on the outer race might be enough to trigger the symptom. Combine that with all of the other issues that contribute to the shakes and it's any wonder it's an issue.
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patanga screwed with this post 06-15-2012 at 07:59 PM
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Old 06-13-2012, 07:50 AM   #37
chasbmw
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Wobbles deaccelerating from 50-30 are almost always head bearings that are too loose.

Just tighten a few Mm at a time until the wobbles go away.

If you change headbearings you will need to readjust them after 500 miles as they settle into position.

I would also add that if you are doing a full rebuild of a thirty year old bike, then new wheel, headstock and swinging arm bearings are a relatively cheap way of helping ensure decent handling and stability when you get to use the thing, better than obsessing over fork alignment to the last 1/10 of a
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chasbmw screwed with this post 06-14-2012 at 03:32 AM
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Old 06-13-2012, 10:11 AM   #38
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I agree with all the above advise but I know from experience that you can have the whole thing brand new and set up this way OR that way, RS fairing or not, and they will sometimes still do it. Just about any bike with a conventional fork will under the right circumstances. There are definitely things that make it worse but making it completely disappear is impossible.
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