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Author Topic: Speed Wobbles  (Read 844 times)

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Offline NewOldSchool

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Speed Wobbles
« on: April 28, 2011, 01:37:46 AM »
Bike runs great and is rock solid up until about 90mph after which it starts to get speed wobbles. These get slowly worse until I back off and get below 90mph. The only other time I get headshake is crossing over divisions in lanes where two slabs of pavement run parallel. It feels like my front tries to follow the groove and I have to let the bike settle down under me. Is there a way to remedy this? Raise or lower the front or rear? Tire pressure? My tires are definitely not worn at all.
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Offline rklystron

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Re: Speed Wobbles
« Reply #1 on: April 28, 2011, 05:07:14 AM »
If everything else is in good shape. Wheels true and balanced. Steering stem bearings in good shape greased and torqued properly. Rear wheel equal distant on both sides (chain adjustment). Rear shocks adjusted for your weight. Front shocks operating properly with good oil with proper weight. Sag adjustment looked at with proper front shock spring preload. Progressive shocks and front springs help as well. Then it may be time to look at a steering dampner. You need to make sure all else is good first. The Steering dampner can and will mask problems elsewhere if you do not check them first. A dampner corrected my death wobble issue at higher speeds. Hope this helps.
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1970 CB750 K0 (Bought in 73)
1972 XL250 (Bought new in 72)
1973 ST90 (Free)
1975 XL250 (Free)
1975 Rickman CR750
1982 CBX1000 Pro-link
1975 CB750 DRAG BIKE
1977 Custom Built CB750 Sturgis Bike (GL front end).
1977 CB750 F2 (Big Resto)
1977 CB750A (Auction Buy)
1978 CB750 K8 (My San Francisco ride)
1984 VFR750 (Bought New)

Offline NewOldSchool

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Re: Speed Wobbles
« Reply #2 on: April 28, 2011, 09:18:00 AM »
The forks have been rebuilt less than 2000 miles ago, I just installed a new chain and made sure the rear wheel was aligned, and the front wheel was balanced when the front end was put back together. Maybe I have the rear shocks set to softly? Ill try everything out thanks!
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Not putting miles on your bike is like not having sex with your Girl Friend so she'll be more desirable to her next Boy Friend.

Offline Duke McDukiedook

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Re: Speed Wobbles
« Reply #3 on: April 28, 2011, 09:23:49 AM »
Year and model of bike.

Has the swingarm been rebuilt- new bushings? New rear shocks? These things along with the steering bearings will make a difference in control.
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Offline rklystron

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Re: Speed Wobbles
« Reply #4 on: April 28, 2011, 09:37:59 AM »
Industrial +1
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1970 CB750 K0 (Bought in 73)
1972 XL250 (Bought new in 72)
1973 ST90 (Free)
1975 XL250 (Free)
1975 Rickman CR750
1982 CBX1000 Pro-link
1975 CB750 DRAG BIKE
1977 Custom Built CB750 Sturgis Bike (GL front end).
1977 CB750 F2 (Big Resto)
1977 CB750A (Auction Buy)
1978 CB750 K8 (My San Francisco ride)
1984 VFR750 (Bought New)

Offline phil71

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Re: Speed Wobbles
« Reply #5 on: April 28, 2011, 06:11:55 PM »
front end rebuilt by who? I recognize those characteristics from a cracked tree top. I rode it for about 45 minutes till i realized what happened. Under really basic conditions it was okay, but grooves/uneven pavement and speed caused some scary things. A loose clamp or misaligned tubes would cause the same kind of thing. Maybe the re-assembly was not done quite right?
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