2012 990 issues?

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by b1kerb0y, May 4, 2014.

  1. b1kerb0y

    b1kerb0y n00b

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    Hey guys!

    Phil here from over the pond!

    I've done nearly 9000 miles on my 990 now and it's awesome!

    It's fitted with abs and when I'm braking at slow speeds with my front brake I get a pulsing through the lever. It's like the brake is going on off on off on off. I'm not braking hard or anything... Just wondering if this was normal? It's not a warped disc because I have checked both and they seem to be fine.

    Also when I travel at speeds between 30mph and 40mph I get a bobbing sensation. It's like the front suspension is going over a really bumpy road when actually the road is really smooth. It's fitted with conti trail attack 2's which I know are good tyres.

    Any ideas?

    Thanks in advance for the help :ear
    #1
  2. TexaNate

    TexaNate Been here awhile

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    The low-speed pulsing sounds a lot like warped something. If it's not the disc, it could very well be the rotor mounting tab. How do you know the discs aren't warped? They have extremely small tolerances - a visual inspection likely won't pick up tiny imperfections. I assume the pulsing occurs whether the ABS is on or off.

    As for the bobbing - it's likely your wheels are out of balance or out of true. The reason it only happens at 30-40mph is the vibrations from your front and rear wheels are going in and out of phase at that speed.
    #2
  3. Chuckracer

    Chuckracer Jerkus Maximus

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    Hi Phil,

    The brake pulse is most likely pad material build-up on the rotors. I've fixed it with a Rotor Hone but it usually comes back eventually. It's actually more of a hard spot on the disc...unusual but not rare.

    The front wheel hop is almost certainly the tire. Lots of Conti front tires suffer this affliction.
    #3
  4. b1kerb0y

    b1kerb0y n00b

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    Wow thanks for the quick replies!

    I have only looked at the discs and checked them by eye, and yes happens when abs is off as well. Dealer has also looked at them and said they are fine.

    Chuckracer- sorry I should of said that it happened when I had the standard scorpions on as well.

    It's going in for a service soon so I'll bring it up with dealer again.
    #4
  5. Chuckracer

    Chuckracer Jerkus Maximus

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    Ah. That sounds like an out-of-round wheel then. It may only be balance, but with both tires?
    #5
  6. TexaNate

    TexaNate Been here awhile

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    +1. I would have the dealer check balance as well as long as he's down there.

    On some Tiger 800s I've heard of bouncing being caused by fork binding from improperly installed front wheels. Just as a quick check (it probably won't make any difference) you might consider loosening the front axle pinch bolts, bouncing the forks a few times to let the forks seat and retightening.
    #6
  7. b1kerb0y

    b1kerb0y n00b

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    Yeah with both tyres it happened. Like I said it only does it on smooth roads and between those speeds. I'll just stick to bumpy roads I guess :D
    #7
  8. Bullskin

    Bullskin Been here awhile

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    I have this same problem and have always wondered what it was. I actually have two sets of wheels and have gone through many tires on both sets. They all have the bounce. That's what has had me so confused.
    #8
  9. renogeorge

    renogeorge Let's ride!!

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    I may have missed it. But nothing said about balancing.....Pad choice can make a big difference as to low speed grabbing. Although I would be looking at the ABS...

    FWIW
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  10. Wantajustride

    Wantajustride Been here awhile

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    I'm going to add that I too have / had the slow speed front end bobbing on my 2012 990R.
    And have went thru a couple tires in 7500 miles. I have not trued my wheels.

    I am not certain and am merely speculating that the issue is not the tire nor the wheel not being true, but in fact could it be that the spring rate of the front forks are to soft. Have you ever noticed how hard the front end dives when moderately braking using more front than rear brake?

    I have adjusted the preload and that helped some. I also have played / experimented with the compression and rebound and it has helped also.

    I guess what i'm saying is,,,Read a bit about suspension set-up and play with your clickers after your suspension is broke in.

    A shop tech at my local dealership has convinced me that it's time to re-spring the front forks which will transform the ride and handling quality. This conversation came up as we were discussing off road handling of the 990.

    Maybe a 990 suspension savvy inmate will chime and and either agree with me or tell me I have no clue what I'm yappin' about.

    WJR
    #10
  11. Jean-Ma

    Jean-Ma Been here awhile

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    I had exactly the same issue on my 990 with the original tire (Pirelli mount). Since I changed my wheels for the Alpina tubeless model and a new set of Karoo 3, this bobbing sensation disappeared.... Many people said that this is coming from the tire itself. I don't know if this is true or not but in my case replacing the tire eliminated the problem.
    #11
  12. renogeorge

    renogeorge Let's ride!!

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    It wouldn't hurt to try stiffening front suspension with compression adjustment. And play with rebound adjustment while you are at it. Increase preload to ride higher in stroke??

    And the same in the rear. A starting point might be to go to the "sport" settings front and rear. I guess the 1190 has such......
    #12