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Old 12-26-2014, 03:04 PM   #1
Excite-Bike OP
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Bluhduh Just finished adventure modding my F650GS and now it has a terrible steering wobble!



It's a standard height 2010 model and ran as smooth as a missile over 110mph when I first got it a month ago but now that I added everything below it's become frightening above 75mph.
It had 4,500 miles on it when I got it and just clicked over 5k now.
Here is a pic from the day I bought the bike

It also has vibrations that have been causing my left hand to fall asleep too. That may have been present all along but took me a while to recognize because I thought it was my new tight un-broken-in gloves but it's clear now that it's from vibrations not the gloves.

Mods:
1. K&N Air Filter
2. TT Mesh Headlight Guard
3. Givi Wind Screen
4. TT 20mm Handlebar Risers
5. TT Hand Guards
6. Beak Extender
7. Wind Deflector
8. TKC-80 Tires
9. SW-MOTECH Top Rack
10. Emgo Travel Trunk
11. Moose Racing Skid Plate
12. Hepco & Becker Crash Bars
13. Leovince Carbon Fiber Pipe
14. Seat Concepts Tall Seat
15. Cricket Bat Rubber Grips
16. Power Controller Throttle Fix
17. Rivco Highway Pegs
18. SW-MOTECH Center Stand
29. Garmin Nuvi 2595LMT GPS
20. R&G Radiator Guard
21. Hepco & Becker Side Racks
22. Caribou/Pelican Hard Cases
23. Camel ADV 2 Gallon Gas Tank
24. Osram 65 watt headlight bulbs

The plan so far:
1. Test ride the bike with top and side cases on and off to see if the handlebar wobble or vibration changes
2. Take it to BMW Motorrad to see if they can fix it by tightening various bolts or adjusting the suspension
3. Purchase Scott's steering stabilizer, Ricor fork valves, soft rubber waffle grips, soft thick leather gloves
4. Consider dumping the TKC-80 tires for less knobby ones and maybe completely upgrading the front forks

From the web:
- Shortening the spacer length used in the forks can help with head shake (What spacers is he talking about?)

- Cranking up pre-load and raising the forks 2-4mm can help by adding weight to the front
(As far as the fork clamp goes, I thought it was the opposite and the longer the forks the more stable and slower turning and the shorter the less stable but faster turning. When I installed the bar risers I actually adjusted the forks to be nearly flush with the top of the clamp to get every last bit of height out of them to to compensate for my adding preload height and tall seat height to the rear)

- Tightening the steering head bearing can cut down on steering looseness and wobbling

- Adding a 17 tooth front sprocket would move the vibey RPM range up higher on the spedo

Any other suggestions? BTW, I weight 195 lbs.

Thanks!

Excite-Bike screwed with this post 12-26-2014 at 03:39 PM
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Old 12-26-2014, 04:01 PM   #2
The Maz
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Have you had tkc's before? You will get more vibration from them. Ive heard people say it was a wobble at higher speeds. If you are new to knobs, it might feel unsettling. Beak extender and larger hand guards will both catch more wind which might exasperate the problem.
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Old 12-26-2014, 04:06 PM   #3
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Quote:
Originally Posted by The Maz View Post
Have you had tkc's before? You will get more vibration from them. Ive heard people say it was a wobble at higher speeds. If you are new to knobs, it might feel unsettling.
I had them on my old DR-Z400 with no hand numbness problems.

The wobbling did begin after the tire install and got worse after the top and side cases were installed.

But the left hand numbness I think was from day one.
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Old 12-26-2014, 04:12 PM   #4
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Hope you get things sorted...
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Old 12-26-2014, 04:18 PM   #5
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I would definately do #1. I've been able to shift weight forward and induce a high speed wobble by turning up the preload on the rear shock and raising the forks a little. However you are doing just the opposite by weighting the rear. Thus I'm not sure what kind of results you would get. I would definately set your suspension sag and see if the behaviour changes.

I run TKC (something like 6 sets) and don't have a wobble, so unless you have a badly unbalanced tire, I wouldn't think it would be the tires.
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Old 12-26-2014, 04:46 PM   #6
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Quote:
Originally Posted by Excite-Bike View Post

When I installed the bar risers I actually adjusted the forks to be nearly flush with the top of the clamp to get every last bit of height out of them to to compensate for my adding preload height and tall seat height to the rear)

- Tightening the steering head bearing can cut down on steering looseness and wobbling
moving the fork tubes in the clamps changes the geometry. I know that the F800gs has a specified amount that is to be above the clamp - but it is a different fork than the F650. (While writing this I realized that this may be why my F800 steering feels weird. I thought it might be because I had been riding another bike and had not ridden it in a while. However, I recently had the fork seals replaced - perhaps they put the fork tubes in the wrong position. I'm out of town so I cannot check that until Sunday).

I suggest moving the forks tubes back to spec and checking the head bearing adjustment. Too tight can cause them to brinell. Brinelled or too loose can cause wobble.
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Old 12-26-2014, 04:49 PM   #7
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Ok I just took off the top and side cases and got it up to 110mph on the freeway with no wobbles at all so I guess it's not the tires which now that I recall were installed the same day as the top rack and case.

So now I'll go back and install the cases and try again. Side first, then top, with all of them empty.

Excite-Bike screwed with this post 12-26-2014 at 05:16 PM
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Old 12-26-2014, 04:57 PM   #8
CycleDoc59
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It is quite common to have head shake if the fork
angle is changed. A properly set up bike drops an
equal amount at each end when loaded. Which is
why the rear spring preload is adjustable. Often the
factory adjustment is not sufficient for heavily loaded
bikes.

Moving the forks up is a remedy, as is use of shorter front
spacers - if installed. This lowers the front of the bike to
better match the rear height.

Loading the rear of the bike - passenger/luggage, is the
primary cause of head shake; if the bike is not leveled,
expect head shake....

But there are many other things to consider, such as tire
pressure (more needed for added weight) steering head
bearing tightness/condition, tire condition/balance/trueness,
wheel bearing condition, rear swing arm bearings/tightness...
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Old 12-26-2014, 05:43 PM   #9
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Ok, now I just got back from hitting the freeway with the side cases installed *empty* and was able to hit 110mph without any significant wobbles, though the wind resistance and resultant twitchiness was noticeable at such speeds no scary gyroscope wobble developed.

So now I'll add on the top case *empty* and make a run before loading any of them with weight.

And just for the sake of argument, what kind of effects might arise from loading the case on one side with heavy tools and the other with lightweight gear?
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Old 12-26-2014, 06:00 PM   #10
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Quote:
Originally Posted by Excite-Bike View Post
Ok, now I just got back from hitting the freeway with the side cases installed *empty* and was able to hit 110mph without any significant wobbles, though the wind resistance and resultant twitchiness was noticeable at such speeds no scary gyroscope wobble developed.

So now I'll add on the top case *empty* and make a run before loading any of them with weight.

And just for the sake of argument, what kind of effects might arise from loading the case on one side with heavy tools and the other with lightweight gear?
It would then be easier to fall down on the overloaded side..(?) Actually,
the bike would have to steered with slight counter-steering, much like
compensating for wind from one side. Not dangerous, should not cause a wobble in itself,
but not wise to heavily load only one side...

Also, a top case on some bikes can cause "wind wag", as turbulence
hits the box from different angles, the bike wanders a slight amount.
Harleys can have that problem. Your bike should not...
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Old 12-26-2014, 06:31 PM   #11
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Screen could be an issue.
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Old 12-26-2014, 08:15 PM   #12
CycleDoc59
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If it might help, my '10 F650 has a pair of Micatech bags,
a Vario topbox, a large tank bag and Madstad windshield.
Fully loaded, including a tent and chair across the seat,
and running well-worn miss-matched tires, It tracks perfectly
w/no tendency to "wobble" at 76mph. (2,500 mile trip in
Nov at mostly that speed..) And it still handles
nicely on bumpy, twisty back roads...
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Old 12-26-2014, 09:40 PM   #13
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You should probably check out the comments in Fark Spring Rates thread.
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Old 12-27-2014, 05:42 AM   #14
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Check your sag numbers I bet your rear end is squating too much and causing the front end to be to light. Most likely you will need a much heavier rear shock spring. Might as well change the front end springs to match your sag needs and run the forks 20 mm higher in the triple trees. Also some front tires are less stable so you may want to try another front the next time you change tires.
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Old 12-27-2014, 08:49 AM   #15
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Quote:
Originally Posted by Indy Unlimited View Post
Check your sag numbers I bet your rear end is squating too much and causing the front end to be to light. Most likely you will need a much heavier rear shock spring. Might as well change the front end springs to match your sag needs and run the forks 20 mm higher in the triple trees. Also some front tires are less table so you may want to try another front the next time you change tires.
This was my first thought. You've made a bunch of adds to the bike but haven't changed the suspension. Now the bike just isn't coping the way it should.
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