New 2013 990 Baja w/ head shake

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by jon6.0, May 11, 2013.

  1. jon6.0

    jon6.0 Been here awhile

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    I just picked up a 990 Baja today. Rode it home and on the highway the handlebars and shaking back and forth. Ride over a bump changing lanes and it gets much worse for a second. Adjusted the rear preload at a buddies house and it still does it. The fork tubes are flush with the triples. I was thinking of dropping them down some. The question is, how much? Could it also be loose steering head bearings?

    Pics of new bike:

    [​IMG]

    [​IMG]
    #1
  2. kaptinkaos

    kaptinkaos Just some nOOb

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    I just picked up the same bike and I'm pretty sure it's that lovely 908RR on the front combined with the uber soft suspension settings in the forks. I will know for certain in about a week when I get back to Canada and spoon something a bit more 50/50 on the front end.
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  3. jon6.0

    jon6.0 Been here awhile

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    I ran an MT21 on my TE449 and had no shake at all on the highway. I'll try setting the suspension to the sport settings and see if that helps before I try dropping the forks through the triples..
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  4. kaptinkaos

    kaptinkaos Just some nOOb

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    You could check the torque also on the stem, but I think you would be able to notice some play in the whole front end if that was the issue. Put the bike on the center stand and move the bars back and forth to ensure nothing is binding or has a sticky spot. Possible the bearing got borked in assembly? Highly unlikely, but possible. Here's a link to the torques:

    http://www.advrider.com/forums/showthread.php?t=310249
    #4
  5. kaptinkaos

    kaptinkaos Just some nOOb

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    Lol, the TE is much smaller and lighter though... And the geometry is different. I like the MT21's, but the set I have is going on the 450. I'll put a Michelin T63 or TKC on the 990 I think. A bit harder of rubber compound.
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  6. jon6.0

    jon6.0 Been here awhile

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    All the suspension settings were the comfort settings. Adjusted to sport just now. Hope it helps a bit. If not I'll drop the fork tubes through a little. If that still doesn't help I'll get a T63 or TKC.
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  7. kaptinkaos

    kaptinkaos Just some nOOb

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    Did you check the stem nut too? Just put the front end in the air while on the center stand and tighten it until you see a little resistance in steering. Then back off a 1/4 turn. Then go put some miles on it and see if anything has changed. Only then would I throw a new tire on, :) (But the 908RR's are well known to be "snakey" on pavement". Down right spooky in the corners sometimes actually)
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  8. jon6.0

    jon6.0 Been here awhile

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    I did not check the stem nut yet. If it really is the front tire, I'm going to be pissed. I've ran many different knobbies on the highway and never felt like that before.
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  9. slidewayes

    slidewayes slidewayes

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    My first set of 908s scared the crap out of me . thats why I built a set of 17" s 20 minutes to change wheels. the best of both world's tell you put a Tarra Flex on the rear now your talking
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  10. NewtAZ

    NewtAZ "did you say tacos?"

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    I just bought same bike with same issue. seems to only happen at higher highway speeds 70 MPH+. i have zero shake offroad. i think the problem is a combonation of soft forks and knobby tires. i took my bike in for its 600 mile service and told the mechanic about the shake and that the front end also dove under hard braking. i have also bottomed the front end twice while off road. the mechanic said he "firmed up the forks dampening 1 full turn. " On the ride home the shake was less noticeable but still there, but not as bad. My plan is to finish off the stock tires (which i LOVE off road), and try a less aggressive front tire. if the shake is still there my next step will be a Emig steering dampener/triple clamp kit.

    oh... and i suggest you dont make any other suspension changes until you figure out the front end. too many changes at one time can make your problem worse. I dont think the rear preload would have anything to do with the front wobble. put it back to stock position and try firming up the forks first. once you have the forks dialed in, then deal with the back end.

    BTW... you have a sweet bike!
    #10
  11. jon6.0

    jon6.0 Been here awhile

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    Changing rear preload affects trail. Which will affect the front end.

    Took it for a test ride and it is still shaking. At 85 mph the bars move 1.5-2". I put it up on the center stand and the bars move VERY easy side to side. Plus now I feel a slight catch in the movement just to the right of center. You can also hear a scraping sound when the bars move through that area.
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  12. kaptinkaos

    kaptinkaos Just some nOOb

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    Well, I've had a lot of different bikes off road and ridden them on pavement too and run just about every type of knob and I too have not felt this particular head shake or twitch like my 990 does set up stock... I will be pulling my front end off to replace with an Emig 20mm offset anyway and I will keep the 908RR on the front to see what effect that has. I'll be going over the stem, bearings and seats with a critical eye also. I'll be looking for any sign of something out of shape or untoward in there. I won't put the dampener on until I know the head shake is gone as doing that will only hide the problem, not make it go away. Plus, you'd be punishing your dampener for something it's not intended to fix.

    I do hope this isn't a manufacturing error or a factory mistake and it seems a bit too coincidental that your symptoms are IDENTICAL to mine. Here I was just was telling myself that 908's are snakey on pavement (because they are, I've run some before), but maybe there is a deeper cause to the head shake... God I hope not because I have 6 days to sort it when I get back to Canada before I leave on a 4000km shakedown ride. :shog

    Try tightening your stem nut up to the friction point (where the bars stop falling freely) and back it off just a tiny bit so they don't wanna fall fast. I'm hoping the scrape you hear is paranoia and that the head shake goes away after you tighten up the front end, :D
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  13. Sevv

    Sevv Been here awhile

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    Really sounds like steering stem bearings. That notchyness you are feeling could be the racestarting to brinel.
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  14. kaptinkaos

    kaptinkaos Just some nOOb

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    Just saw this too... Could spoon off the front tire and check your rim strip. I've never seen this before and in my opinion it would take effort to screw up a rim strip this bad, lol!

    http://www.youtube.com/watch?v=gq-ux3YsSF8
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  15. kaptinkaos

    kaptinkaos Just some nOOb

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  16. tacosupreme

    tacosupreme Been here awhile

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    When I got my new dakar home noticed the genius dealer mech didn't align the rear wheel and I had some head shake coming out of corners on the throttle...I used a set of digital calipers to get it close enough and now no problems.
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  17. Night Shadow

    Night Shadow Adventurer

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    Mine does the exact same thing starting at about 80mph. I'm really thinking/ hoping that it's the tires. If I go to pass a car meaning accelerate quickly from 55 it'll start shaking or weaving pretty bad. If I accelerate at a much slower rate then I might be able to get to 85 with minimal shaking or weaving. I bumped the tire pressure up a little from where the dealer had it and it might have helped some.

    As far as the scraping noise mine also did that after I removed the upper fairing. After I had reinstalled them the noise appeared. One of the vent hose clamps was rubbing the left fork. Readjusted it and fixed the problem.

    I've read all of the post about people going 100mph on this bike and I was thinking no way. So I really think it's the tires. I'm swapping mine out soon for an upcoming trip.
    #17
  18. max2

    max2 Been here awhile

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    Normal for a brand new 908, they will scare the crap out of you till the wear in. Try lowering the rear tire pressure to give it a larger footprint. I noticed an improvement after 4-500 miles.
    #18
  19. CROM

    CROM Canuck del sur

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  20. DeepInIt

    DeepInIt Long timer

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    +1s for two posts

    First, wait 200 miles and the tires will get better.

    Second, shake in the front end is often issues in the back end.

    i dont think it is something serious with the front end, these bikes get setups that do this now and then. It isnt the design, i have run my bike to 200 kph, granted easier with Scorpions but my knobbies easily do 180. Do check your rear alignment. Suspension adjustments are a big step but stiffen front, soften rear to see if it helps.

    Balance tires before changing.
    #20