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One thing to try would be to go to a lighter weight fork oil.Do the forks work up and down smoothly when you hold the front brake and rock the bikeforward and back? If everything is working properly the bike wouldn't be hopping. There's a possibility that the hopping isbeing caused by a resonance with the Vetter fairing's flexing. Have you tried taking the Vetter off and seeing how the bike behaves?

As for top speed, my 86 had no difficulty exceeding 100mph and it got there pretty fast.

 

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I'm thinking that Mobil 1 would be a bit heavy bodied for fork oil. About the only way you're likely to solve this one is to disassemble the forks and see what's going on. I'd sure want to see the bushings. Something's gone bad in there, the bike didn't ride like that new. Have you tried the bike with the Vetter off? It still might be a resonance problem between the bike and the fairing, a road test with the Vetter off might get you aimed more precisely at the problem.

 

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westco wrote:

the forks do not slide in and out unless it hits a bump. Thanks to all again, Gary

I think we have the answer to your problem right there, Gary. The forks should be working in and out almost all the time. As you ride even on a fairly smooth road the forks will be working. There is something binding yours. Try riding slowly and lightly apply the front brakes. Even a very light touch on the brake lever should cause the forks to move in. I'm thinking possibly bad bushings on one or both forks, a bent fork tube, or badly gummed up oil passages. I still think you're going to have to disassemble the forks to solve this one.

 

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I find it unlikely that its a problem endemic to all 78s. If it's not, it's fixable. The PO of your bike says it didn't do that before. There are a couple of things you haven't tried that might give some results. One is to remove the fairing and see if that makes any difference. You mention that the Vetter bobs. How do you know it isn't interacting with the forks at other speeds? The other thing worth doing is to disassemble the forks and check the bushings. If the bearing surfaces are badly worn it's highly likely the fork will have stick/slip problems.

 

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Gary was saying his did it at 25-35mph. It's interesting that this is also the most common speed to have the wobbles. That's why I was wondering what would happen if he took the Vetter off, if it's not solidly mounted, and he does say it bobs a bit at high speed, it seems that the fairing and the bike might be having a weird resonance in the front end.

 

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The tendency to fall inward during a slow turn is also indicative of head bearings that need some preloading torque. Tightening up the head bearings cured my 1200 of that tendency.