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-   -   F650GS Handlebar Shakes Wildly with full luggage at > 130kmh (http://www.advrider.com/forums/showthread.php?t=857700)

peterang 01-23-2013 04:12 AM

F650GS Handlebar Shakes Wildly with full luggage at > 130kmh
 
Hope somebody can advice me how to resolve this.

I ride a F650GS Twin on factory standard shocks with a pair of Hepco & Becker Xplorer Panniers 30/40L.

When I ride without the panniers, I can ride up above 160kmh without any issues.

With the Panniers fitted and loaded, preload cranked to the max, riding anything above 130kmh and the handlebar shakes wildly. I had to reduce my speed to regain control.

I am guessing that it might be a rear shock issue - not being able to handle the load. (I'm about 68kg fully geared and the panniers with load is about 30kg total)

Would changing my shocks solve the issue?

Snowy 01-23-2013 04:38 AM

I can't remember if the 650 forks can be lowered in the triple clamps. If they can, load her up and run it, then lower the front end 20mm and try it again.

A few of us have had similar issues with F800s and that seemed to fix it.

My F800 is significantly taller than standard, especially in the front. I think that with full knobbies as it has now it would be nearly uncontrollable without the steering damper.

GH41 01-23-2013 05:26 AM

"with load is about 30kg " If my conversion is correct that may bepart of your problem. GH

machinebuilder 01-23-2013 06:56 AM

After doing conversions to pounds, I see you're 150lbs and your luggage is 64lbs.

The first thing I suggest is to check your sag, I'm not sure about the F650 specs, but it is ususally reccoomended to have sag set to 30% of the travel.

Also check your tire pressure, it can have an effect.

try riding with the bags empty, the wind buffeting can also effect things.

Slow down..................:evil

It'sNotTheBike 01-23-2013 08:31 AM

Steering head bearings & swing arm bearings
 
It is possible the bearings at the steering head and / or the swing arm are worn
enough to allow slop which should not exist. Such slop can cause a high speed
head shake which can be exciting. The change in weight distribution caused by
adding the panniers could exacerbate the potential for head shake by shifting the
weight bias toward the rear of the bike, thus "unloading" the front end of the
bike and allowing the steering head a bit more freedom to move about.
So I'd look at the steering head bearings first of all, then check the swing arm bearings.


After that, check ride height both without a load and with a load. You may need
a rear spring which has a higher rate to compensate for the added load of panniers.
The shock has much less influence on ride height than the spring does, whether it
is a high-pressure nitrogen filled shock or not.


In any case, best to go through the entire bike and check everything, including wheel
balance and all other suspension-related items. Adding a steering damper might mask
the symptoms but will NOT cure the cause. You need to find the root cause because
the safety of the bike could be compromised by whatever is causing the shake.


And have a very close look at the front forks where the axle passes through. Some
of the front forks on some of these bikes have had "issues" ( they fail structurally while the
bike is under way ) and that is potentially disastrous. Look for cracks in the lower fork leg
near where the axle passes through the lower fork leg.


Good luck.


.

markymcd 01-23-2013 06:58 PM

You might also have a misbalance in your front wheel. BestRest has a product (i think they're called DynaBeads) that go inside your tire and go where they are needed when rolling. The misbalance will be more distinct with the luggage on the back.

But also per a previous inmates comments, check your head bearing. Without it having it properly checked you would probably feel a clunk over big bumps if it was loose. Quite common from the factory.

I've had the bike comfortably at 140kmh with full luggage and passenger... and even at 160kmh on gravel with full luggage (no passenger).

good luck,
Mark

JustKip 01-23-2013 07:09 PM

Your 68kg + 30 kg for luggage can't be the cause of your problem.
I weigh 107 naked, and any pillion would weigh quite a bit more than 30kg.
Wind resistance of the boxes may be part of it, and as others have said, check your steering head bearings. The wind input on the boxes may be unloading the front enough for looseness to cause the front end to wonder. Otherwise the rear shock would be suspect. Check it for compression while sitting still, and make sure the swingarm pivot bolt is tight.

peterang 01-23-2013 10:49 PM

Thanks for all the advice so far. I will go through them and post back my findings.

Anymore suggestions are most welcome.

Reaver 01-25-2013 06:49 AM

Quote:

Originally Posted by peterang (Post 20562189)
Anymore suggestions are most welcome.


Dr. "Does it hurt when you do this?"


Patient: "Yeah."


Dr. "Then don't do that".



:hmmmmm





I know, I know........:stfu

GH41 01-26-2013 05:11 AM

Quote:

Originally Posted by JustKip (Post 20560790)
Your 68kg + 30 kg for luggage can't be the cause of your problem.
I weigh 107 naked, and any pillion would weigh quite a bit more than 30kg.
Wind resistance of the boxes may be part of it, and as others have said, check your steering head bearings. The wind input on the boxes may be unloading the front enough for looseness to cause the front end to wonder. Otherwise the rear shock would be suspect. Check it for compression while sitting still, and make sure the swingarm pivot bolt is tight.

A passengers weight would mostly be forward of the axle. His cases place the weight mostly behind the axle. GH

lunaticTR 01-26-2013 06:57 AM

Not a luggage problem.
 
I got the same 2008 motor. I have 45lt cases on both sides on a swinging givi mount. One side is hanging out more because of the muffler. I put at least as much load in them. However I have a 55lt topcase as well. I weigh close to you with gears. I do not increase the preload in the rear shock though, just a few turns. I do not have any shakes at 140+kms when I am going straight (not that I do it all the time, just in short burst because the milage drops drastically). At the curves it is the rear shaking thanks to the swinging mounts. Must be something wrong with your front end - I mean the bike's front end :rofl

RheinGold 01-28-2013 01:29 PM

I've a 2012 F650. Rode it cross-country (6,000 miles) fully loaded with Jesse bags, top case, passenger, etc. I've had NO shaking problems at 70mph+, on gravel, dirt, in rain, etc.

Suggest you look at the head bearings and tire pressure. Also, my preload is somewhere between 1/4 and 1/2. Perhaps yours being at full preload is adding to the problem.


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