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Motorcycle death wobble


H3re2Learn's Avatar
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05-03-16, 02:04 PM   #1  
Motorcycle death wobble

Before you read this please if you're here to criticize keep moving, now... 1979 honda cb650 brand new perelli on the rear and I get the death wobble in triple digits. If you don't know what that means I'm afraid you can't help me. Already took it back to the tire shop to have them recheck alignment and they said it was fine. Any other thoughts?

 
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05-03-16, 02:11 PM   #2  
Usually you get the wobble from the front tire. If the front tire is worn, replace it.
Also check the fork bearings. If they are worn or loose, they could also cause wobble.


Woody


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05-03-16, 03:31 PM   #3  
With all your disclaimers and warnings, I really don't feel like answering, but I will. I will concur with Goldstar that front wheels generally cause the impetus that vibrates through the bike causing the wobble. With a bike of that age, I would also check bearings on both axles.

 
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05-03-16, 03:42 PM   #4  
Did it do it before the tires were put on?

I had a death wobble at high speed on an 02 widegide I had. It was caused by the rear shocks one having more tension then the other.. They were adjusted wrong from the person I bought it from...


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05-03-16, 03:55 PM   #5  
Been there done that on a BMW 500.
Called a high speed wobble.
Broke my collar bone, took the top of my helmet off when I skidded across the road and hit a guide post.

 
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05-03-16, 11:19 PM   #6  
The "disclaimer" as you call it, was simply because I didnt want to hear people tell me to slow down! \

It did NOT do it before the new tire only the rear was replaced but thanks for mentioning shocks I do need new ones maybe the new rubber is causing them to act up. the front tire has proper pressure and even wear, this wobble actually occurs also around 60 when changing lanes on a concrete highway, just that little lip where the lanes meet causes the wobble I replaced fork seals and front wheel bearing last year but I did put the recommended ATF but I think ATF is only 5w so I was thinking about using actual fork oil and putting some 15w in there. maybe the softer forks cause it. will look into fork bearings tomorrow.

 
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05-04-16, 02:36 AM   #7  
Telling a motorcyclist to slow down is like telling a dog to quit barking I would try the fork oil, too, since it wasn't mentioned originally. I think changes on two wheels are magnified much more than they would be on four.

When I restored British sports cars last century, I put on a set of Bridgestone tires on my TR6. The car came from the factory with Michelin red lines. The walls of the Bridgestones could not take the lateral sway of the car as well as the Michelins, so you always felt out of control cornering.

 
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05-04-16, 02:36 AM   #8  
How does the bike track? Since it was when the tire was put on I would say the tire may be need to be realigned and everything was torqued wrong..

Swing arms plays a factor.. Was the front tire torqued correctly?

It can be many things but you need to go back to see what was actually done to the bike and go back and loosen all the bolts and re torque and or realign...


Mike NJ




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05-04-16, 05:20 AM   #9  
Maybe inherent for the series? My 1972 CB450 gave me a bad high speed wobble when it was practically brand new. Scared the bejeebers out of me (which is hard to do when you're 18), so after that I kept it under the wobble speed. Pretty big difference between a '72 450 and a '79 650, of course.

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05-04-16, 05:42 AM   #10  
I'll agree that this is a long shot & probably not your issue based on the info you provided but just to mention this if all else fails.

I had a '81 Suzuki GL650 with an aftermarket windshield that got out of alignment & would give me that wobble after about 90 mph.

Good luck......

 
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05-04-16, 10:03 AM   #11  
My original thoughts were based on a problem I had with my V-30 Magna. New front rubber cured it.
My current ride (VTX1300C) has had some problems with the neck bearings. So far mine is good but many riders have changed them out.


Woody


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05-04-16, 11:13 AM   #12  
I don't ride motorcycles but can wheel balance issues cause this behavior? You changed the tire and nothing else so it seems the answer is likely there since that's the only variable you mention having changed.

 
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05-04-16, 12:35 PM   #13  
Balancing is a normal part of tire replacement. Some use weights that attach to the spokes; some attach to the rim; and others use dyna beads in the tire.


Woody


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05-04-16, 01:48 PM   #14  
You got some good advice here... Like I said torquing the bolts and tire alignment is critical.. Im not familiar with the Hondas other then the dirt bikes I had as a kid..

Please let us know the outcome as it may help many..

I will ask my vintage Honda buddy next time I see him.. He collects and restores them.

Also this may not be the best forum for your question..

My issue as I stated was rear shocks out of adjustment.. The rear suspension can be adjusted at each shock firm or soft with a spanner wrench.. Not sure if the hondas of that era did that..

Mine one shock was two click off the other..

But the wide glides are notorious for wobble.. Look at The wide forks and the rake the stock bike has.. Hence " Wide Glide" And the 21" er...

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Mike NJ




"The problems that exist in the world today cannot be solved by the level of thinking that created them".


- Albert Einstein



 
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