1. rattis

    rattis Long timer

    Joined:
    Apr 3, 2010
    Oddometer:
    1,980
    Location:
    East of the seas of Kattegat
    My 990 overheats, in slow traffic and i Colombian low land temperatures and in city traffic the thermometer crawls up to the second but last bar and the fan is running the whole time blowing hot air on my left knee.
    The only thing that I can see is that the coolant level never moves in the expansion bottle, always sort of mid level.
    It warms up reasonably quickly and according to a mechanic in Guadalajara the thermostat is ok.
    He's changed the coolant by the way and it made no difference at all.
    It's bit depressing sitting in rush hour traffic and knowing it's overheating and maybe it'll stall due to high temp.
    The Colombians will lynch me!
    waterpump?
    burp?
    It runs well by all standards.
    #1
  2. jwalters

    jwalters Farkle Proliferator

    Joined:
    Jun 26, 2005
    Oddometer:
    2,529
    Location:
    Little Marais, MN
    I'd make sure it's burped. Get that front wheel 3 feet off the ground and see if the radiator can take more coolant.

    #2
  3. Two Moto Kiwis

    Two Moto Kiwis Homeless Somewhere

    Joined:
    Apr 12, 2007
    Oddometer:
    4,222
    Location:
    Wanaka, New Zealand, ....What Trip!!!
    Try the burbing first, Maya always ran 5 bars in traffic, twice 6 bars when I forgot to turn the headlight off and it was 40 plus degrees, that is now fixed with an off on switch.

    Short of that the second fan mod, forget the lower thermostat it is a waste of time.

    Welcome to South American heat ... stay in the mountains and out of the cities!!:clap
    #3
  4. ICERIDER

    ICERIDER Adventure Rider

    Joined:
    Jun 23, 2006
    Oddometer:
    855
    Location:
    Stanley Falkland Islands
    I remember a 990 guy had this a few months ago. He even checked the thermostat in boiling water and was convinced it was working. If I remember correctly it was the thermostat after all. Just wasn't passing enough flow through the rad.

    You can check the pump is working by taking the rad cap off when it's cooled. Start the motor and you should see the flow coming up the right side of the rad. Not too many revs or it'll shoot all over the place!

    Does your bike have 2 fans? Some guys fit the stat switch that brings the fans on earlier, but if your system is serviced correctly it should handle normal ambient temps without overheating.

    Try fitting a new rad cap and thermostat first perhaps?
    #4
  5. gearheadE30

    gearheadE30 Long timer

    Joined:
    Jan 20, 2012
    Oddometer:
    1,388
    Location:
    Indiana
    These bikes can be a bit difficult to completely bleed, as far as the cooling system goes. Mine has a small leak at the pipe that comes out of the water pump cover, and I've noticed that as it leaks, the temp goes up faster and faster. It doesn't take much air to make a big difference in a relatively low volume system like the LC8's.
    #5
  6. Tee2

    Tee2 I SAID! Woo Hoo!

    Joined:
    Oct 20, 2009
    Oddometer:
    1,415
    Location:
    NE Mesa, AZ near Usery.
    I have the same problem when it's warm here. When I asked about it here most of the replies where the 990's run hot.
    #6
  7. gefr

    gefr Life is a trip

    Joined:
    Nov 26, 2005
    Oddometer:
    4,635
    Location:
    East Med, Greece
    This obstructs air flow. Try an aluminum rad guard instead, if you think it is needed for off road adventures.
    You say level does not move in the overflow reservoir. Maybe you need to recheck your thermostat is operating?
    For bleeding, a good practice is to squeeze the hose. Helps push the air out.
    Cheers.
    #7
  8. bikyto

    bikyto Dans le doute...gaz!

    Joined:
    Jun 15, 2009
    Oddometer:
    2,324
    Location:
    Northern Cali
    My coolant level moves in the reservoir every time I use the bike and comes back to the same level on a cool engine.
    I would burp the system if yours doesn't fluctuate at all. :freaky
    #8
  9. Balsta

    Balsta Been here awhile

    Joined:
    Feb 11, 2008
    Oddometer:
    400
    Location:
    Chilly Northern Europe
    Two summers ago my 990 overheated (often 6 bars on the thermometer). Reason was the waterpump impeller was in contact with the housing. When I opened the housing I found a worn impeller and the pump housing was damaged too. I guess the issue was a missing retainer on the shaft but I didnt put any attention to the exact reason. I simply replaced impeller, shaft, seal, bearing and housing. Success! Since then, always 4 bars on the thermometer with 5 bars only in extreme situations.
    #9
  10. Sawo

    Sawo Adventurer

    Joined:
    Jul 1, 2013
    Oddometer:
    12
    Location:
    Saarlouis, Saarland
    My 990 also overheated last summer. I installed a second fan and an aluminium radiator guard. Hope that will help for the future.
    #10
  11. procycle

    procycle Long timer

    Joined:
    Jun 7, 2007
    Oddometer:
    3,383
    Location:
    Center of the DR650 universe
    CJ Designs has a kit to add a second fan to the right side radiator. I installed it and have never had overheating since.
    #11
  12. geometrician

    geometrician let's keep going...

    Joined:
    May 25, 2008
    Oddometer:
    1,084
    Location:
    West-By-God Virginia
    Sounds like you need to completely remove air from the system & check your thermostat & radiator cap. Make sure your coolant is properly diluted. Consider a CV4 higher-pressure radiator cap, costs about the same as OEM replacement.

    Are you referring to the fan switch? Not true at all- for the money works better than a 2nd fan. I tried the switch alone & it keeps overall temp lower, the 2nd fan (which I also have) just brings the temp down faster.
    #12
  13. ICERIDER

    ICERIDER Adventure Rider

    Joined:
    Jun 23, 2006
    Oddometer:
    855
    Location:
    Stanley Falkland Islands
    How can a higher-pressure rad cap help it run cooler? It raises the boiling point but doesn't dump heat.

    I can see how the lower temp fan switch can help, by dumping heat sooner instead of waiting for it to build up.
    #13
  14. buzybraza

    buzybraza Been here awhile

    Joined:
    Feb 28, 2010
    Oddometer:
    422
    Location:
    Escondido, CA
    1-install second fan (from CJ or ADV Machines) http://www.cjdesignsllc.com/products/dual-fan-rally-kit-ktm-950990-adv/ http://www.advmachines.com/product_p/rallyfan-1001.htm
    2-install lower temp fan switch http://www.ktmtwins.com/ktm-950-990-690-rc8-thermostat-switch http://www.cjdesignsllc.com/products/radiator-temperature-sensor-ktm/
    3-run evans coolant instead of regular coolant http://www.evanscooling.com/products/coolants/powersports-coolant/
    4-test thermostat
    5-burp system

    If your bike boils after all this, then set it on fire and collect the insurance check. :lol3
    #14