Overheating KTM 640 Adventure

Discussion in 'Thumpers' started by rapiti, Nov 7, 2004.

  1. Happe

    Happe Adventure Bike Spanner Man

    Joined:
    Sep 25, 2003
    Oddometer:
    694
    Location:
    Wales UK

    Hi Rapiti,

    just a quick one,
    the temperature gauge is where on your bike (should be near the cyl head in the small cool circuit before the thermostat.)
    The tempswitch for the Fan is where? (should be near the bottom of the right radiator and in the big cooling circuit behind the thermostat)
    Three guesses what makes trouble in your cooling system :evil

    cheers

    Stefan

    If you need more cooling rip out the thermostat like on the Rally bikes ;-)
    #21
  2. AusieRob

    AusieRob Just Gas It!!

    Joined:
    Aug 19, 2004
    Oddometer:
    377
    Location:
    San Francisco
    Well you maybe right, BUT you sure one of those terminals isn't wired back to a ground point, somewhere? I would be surprised if it was done much differently to what's shown... I didn't have a KTM wiring diagram in my pocket at the time and I did say "The wiring shown is indicative" :brow ...
    #22
  3. RedDread

    RedDread What I can While I can.

    Joined:
    Mar 14, 2007
    Oddometer:
    32
    Location:
    Idaho
    This thread is nearly a decade old but relevant to my decade old ride.
    A couple of years ago my 640 overheated and blew off the hose linking the radiators. Once that was addressed the clutch bled out. I replaces everything clutch associated from the handlebar to the motor case and the problem stopped. http://advrider.com/forums/showthread.php?t=131919&page=2

    This August the old lady and I were tooling around on Highland Valley Trail when the "TOO DAMD HOT" red light flared up, and the bleeding clutch lost pressure again!

    Anybody else out there seen this?

    #23
  4. Happe

    Happe Adventure Bike Spanner Man

    Joined:
    Sep 25, 2003
    Oddometer:
    694
    Location:
    Wales UK
    HI there,

    you need to swap the temp sensor for the Fan, right radiator bottom.
    If on ride and it runs on idle for 5 minutes the fan should come on.
    The warning light sensor sits in the cylinder head and there it will be even hotter than in the radiator.
    Also swap the radiator cap. If the hoses blow before the capvalve releases preassure something is not good with the cap.

    The hydraulic slave cylinder of the Lc4 early models, 03 & 04 are known for leaking. There're a few aftermarket billed ones available, get one of them and the leaking is history. Or get one of the last Lc4 models 06/07

    cu
    Stefan
    #24
  5. bmwktmbill

    bmwktmbill Traveler

    Joined:
    Jul 16, 2005
    Oddometer:
    5,986
    Location:
    Traveler
    Make sure the electrical connections to the sensor are tight.

    If the fan cycles it's not the sensor.

    Any air bubbles in the radiator when you run with the cap off?

    bill
    #25
  6. Dee Cee

    Dee Cee Been here awhile

    Joined:
    Mar 6, 2006
    Oddometer:
    584
    Location:
    Newlyn. Victoria.
    Hi all,
    I have a 2003 Adv that I have owned for nearly nine years and I really love this bike. So I am giving it a birthday present and I am going to go right through the whole bike, it has over 80,000 kls of faithfull outback travel under her belt and as we all know there isn't much out there straight out of the box that stacks up to these old girls.:clap
    Has anybody replaced their coolant hoses with the silicon ones available around the traps? There seems to be two versions, one is twice the price from the UK and I guess that the cheaper ones are Chinese based one way or another.

    All advice greatly appreciated.
    #26
  7. Hipster

    Hipster Long timer

    Joined:
    Aug 31, 2004
    Oddometer:
    2,436
    Location:
    Mpls, Mn.
    I've been happy with ASI brand Silicone hoses from China, just make sure you buy hose clamps made for the softer Silicone hoses.
    #27
  8. Dee Cee

    Dee Cee Been here awhile

    Joined:
    Mar 6, 2006
    Oddometer:
    584
    Location:
    Newlyn. Victoria.
    What's the difference with the these type of clamps?
    #28
  9. Laromonster

    Laromonster Lean, mean pacifist machine

    Joined:
    Jun 28, 2004
    Oddometer:
    2,053
    Location:
    Behind you
    the edge of the clamp is rolled slightly over, so it wont cut into the hosematerial
    #29
  10. Hipster

    Hipster Long timer

    Joined:
    Aug 31, 2004
    Oddometer:
    2,436
    Location:
    Mpls, Mn.
    #30
  11. Aussie Jase

    Aussie Jase Been here awhile

    Joined:
    Mar 1, 2007
    Oddometer:
    730
    Location:
    Living back in civilization
    This one is related and after not getting any results through Google was hoping for some info from the asylum;
    Does anyone run a coolant reservoir (overflow tank) on their 640 Adv.
    I am asking as I believe the bike will through running hot say slow going high rev work in technical sections throw some coolant out of the overflow as a matter of course. Add to this a couple of drops and a lengthy trip reducing the need to carry spare coolant would be handy.
    These are thoughts based on some of my experiences resulting in a bottom hose blowing off on me - maybe I'm on the wrong track all feedback greatly appreciated.
    Cheers Jase
    #31
  12. bmwktmbill

    bmwktmbill Traveler

    Joined:
    Jul 16, 2005
    Oddometer:
    5,986
    Location:
    Traveler
    Is your temp gauge working?
    How many bars are you getting?

    Do you hear the fan kick in when the machine just sits and idles?

    bill
    #32
  13. Aussie Jase

    Aussie Jase Been here awhile

    Joined:
    Mar 1, 2007
    Oddometer:
    730
    Location:
    Living back in civilization
    Hi Bill
    Runs on 4 bars for normal running progressively gets hot when slowly crawling through sand dunes heavily loaded or slowly ducking and weaving through paddocks that resemble rubble pits.
    Fan kicks in when it should and it coughs a little coolant occasionally without the overheat light or flashing bars of death coming in.
    My main issue is ensuring I don't need to top the coolant up after a hard ride through slow going high reving technical stuff all day.
    Cheers Jase
    #33
  14. wrk2surf

    wrk2surf on the gas or brakes

    Joined:
    Dec 16, 2007
    Oddometer:
    8,713
    Location:
    THE exact center of California/Bass lake/Yosemite
    I used to overheat my 625 regularly but never lost enough coolant to warrant it. Actually if you run the coolant above the first fins you are apt to boil it out... wow old thread

    I have seen some rig up bottles however.
    #34
  15. bmwktmbill

    bmwktmbill Traveler

    Joined:
    Jul 16, 2005
    Oddometer:
    5,986
    Location:
    Traveler
    Ya, I've seen the bars of death several times, you could stick a therometer in the radiator coolant to see what temp you are actually running.

    Mine would get hot in the woods if I let the revs drop for too long. Better to keep them up.

    There are two different fan thermoswitches, one kicks in sooner than the other.

    The radiator cap has a pressure release function, do you see air bubbles when you run with the cap off?

    Guess you could inspect the impeller in the pump.

    bill
    #35
  16. Aussie Jase

    Aussie Jase Been here awhile

    Joined:
    Mar 1, 2007
    Oddometer:
    730
    Location:
    Living back in civilization
    Nah... no bubbles when running the motor with the cap off (even give it a bit of decent rev and nada!).
    I used to run a Trail Tech on my old 2001 640 ADv that was great as I could actually read the temp and gauge a base temp for different types of operating styles - not a big fan of bars that calibrated against nothing :puke1

    I realize the cap has the pressure release function; I could also buy a new cap see if that changes anything keeping in mind day trips are not an issue its only I don't want to have to be concerned with carrying spare coolant (i have been introduced to engine ice - its expensive over here but it appears to be a decent coolant and I would rather save every drop than let it spew out over the place) :evil

    The main issue I have is having to pick my way through very slow going areas - if the bike is moving at a reasonable pace (above 40ks ) it's not much of an issue the problem was highlighted when I had to follow an old track that no longer physically existed and I was dodging washouts, rocks and wooden stakes while heavily loaded on a long ADV trip.

    Cheers

    Jase
    #36
  17. Aussie Jase

    Aussie Jase Been here awhile

    Joined:
    Mar 1, 2007
    Oddometer:
    730
    Location:
    Living back in civilization
    Yep resurrecting this old thread again.
    Its indexed so should hopefully be useful to others.

    The bike is still spitting coolant and it got dangerously hot during a cool day on this slow ride
    http://www.advrider.com/forums/showthread.php?t=1061136
    Believe me it got worked hard.
    On the day it spat out 200 ml of coolant from below the fins.
    I am using engine ice, a recovery tank has just turned up today which I will fit and test tomorrow.
    Besides a radiator or fan upgrade any other suggestions?
    Keep in mind it's now our cooler weather, normal road cruising 50km/h + does not phase the bike.
    Am I expecting too much from a dual sport and should I just stick with my Honda xr400 for the slow technical stuff.
    Cheers AJ

    Attached Files:

    #37
  18. 2 SPOT

    2 SPOT bring the rape whistle

    Joined:
    Dec 14, 2005
    Oddometer:
    6,373
    Location:
    Payson AZ
    since installing a manual switch so i can turn the fan on when i want i havent had much issue. the single stock fan moves plenty of air, it just needs to come on and stay on when the bike is off road.
    #38
  19. Aussie Jase

    Aussie Jase Been here awhile

    Joined:
    Mar 1, 2007
    Oddometer:
    730
    Location:
    Living back in civilization
    Dumb question - did you also add a fan or just a switch on the OEM fan?
    Cheers AJ
    #39
  20. 2 SPOT

    2 SPOT bring the rape whistle

    Joined:
    Dec 14, 2005
    Oddometer:
    6,373
    Location:
    Payson AZ
    just a switch to bypass the thermo switch. if i have the switch off the bike will still turn on the fan if it needs to.
    #40