Overheating KTM 640 Adventure

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

  1. rapiti

    rapiti IOR Veteran

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    Went on a woods ride yesterday, and had some cooling issues. This has been brewing for a while, and I have some questions.

    1) Do the "supercool" (I forget the names) liquids do more harm than good? Better than ionized water? Recommendations (that you have used!)

    2) The idiot light comes on 62 seconds before the fan kicks in. What's up with that? The fan used to come on first by a good while. What deterioration is this a sign of?

    3) After riding with the idjut light on for a while, the trail crossed the road, and I went for a cruise on the road to get some air flow. It took a lot longer than I had expected for the temp. light to go out. Later, I even had it come on while doing 55-60 on the road! Does this point to the water pump? Where else?

    I plan on flushing the radiators, checking the thermostat, and maybe replacing the water pump impeller. This is all new to me. Any hints/suggestions? I apologize if this has been covered before. Search (and my memory) isn't what it once was...

    Gracias,

    Paolo
    #1
  2. markjenn

    markjenn Long timer

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    At highway speeds, you should have plenty of cooling capacity so if you're getting the light on while at speed, you've either got a bad sensor or a serious issue like insufficient coolant, trapped ar in the system, or a bad water pump.

    The cooling fan and the high temp indicator are on separate circuits.

    I'd first flush the system and make sure you have good coolant. Then I'd look to the thermostat. Finally, the water pump. If you're losing coolant, the cap might be bad.

    If the bike has no other overheating symptoms, it's possible that everything might be explained by the idiot light sensor coming on too early. Normally, the cooling fan comes on much earlier than the high temp light, so I wonder if it's possible that everything is fine - just the light is coming on prematurely.

    I wouldn't mess around with water wetter right now. This is a band aid and would just mask the symptoms slightly.

    - Mark
    #2
  3. inte

    inte neophyte serendipity

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    I have an '03 640 Adventure with similar symptoms. When I first got it, the thing rarely got above 3 bars. A few months later (& to the present) it hits 6-7 bars & I've had the temp light come on a couple times.

    I tried water wetter & Engine Ice and, if anything, it made it worse! Deionized water & Motorex coolant seems to be the deal - water wetter doesn't seem to affect anything too much - can't recommend Engine Ice - at least for this application.

    Here's the interesting thing - I'm in the somewhat-unique position of having had 2 separate IMOs in my 640 within the 1st year. The first computer rarely went above 3 bars and never went above 4 the whole time it was in. The second computer runs at 3-4 bars on highway & will jump to 5 at stop lights on a regular basis. I pulled the thermostate & water pump - both good. No air in system (checked bleed hole near spark plug), flushed system 3 or 4 times & tried different coolants...

    These computers seem to be calibrated differently!

    I'm also thinking the 640s (& the 950s from the reports I hear) are fairly succeptable to weather/temperature changes. My bike rarely went over 3 bars in winter, in summer I find it at 4-7 bars a lot - though in Southern CA there's not a huge difference in summer/winter weather...
    #3
  4. cbob

    cbob Been here awhile

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    Be carefull with deionized water as it will suck the ions out of any metals it comes in contact with. Deionized water is pure H2O molecules, which sounds good, but has no mineral content to neutralize the water. You need SOME mineral content or the DI water will leach the minerals right out of the cases. End result is holes in very expensive parts!

    Distilled water is a much safer liquid for cooling (with aprooved anti-freeze, of course).

    - c
    #4
  5. inte

    inte neophyte serendipity

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    I zoned ... sorry. Meant distilled ... that's what the big jug I have in the garage says. Didn't know that about deionized though ... interesting.
    #5
  6. Reformed DucFlogger

    Reformed DucFlogger Inventor Of The Wheel Mk2

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    Would be interesting to stick a couple of those racing self-adhesive temp strips on the rad & case to see just what temp the bike runs at vs. what the IMO says.

    Have been thinking of doing that on our 950 & 640 Advs.
    #6
  7. sstodvictory

    sstodvictory Been here awhile

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    To pass along a tip I learned at the Yahoo XR650R forum, try Evans Coolant.

    http://www.evanscooling.com/index2.html

    I can't vouch for it because I haven't tried it yet, but I'm going to. The XR650R looses heat exchange capacity at high altitude like all thumpers, I suppose. Several riders from Colorado wrote that it solved the problem for them.

    Steve
    #7
  8. Katoum

    Katoum Adventurer

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    May be as simple as the temp sensor in bottom of rad that opens and closes the ground circuit to the fan motor is getting out of spec, or acting irregular, I had one on my RFS525 do the same thing. Finally quit altogether, simple ten minute job to change, and not very expensive. You could even pull it out and test in pot of water on the stove with a candy thermometer, and a ohm meter across the leads and check to see if it consistantly opens and closes at the same temperature. Just make sure you suspend it in the pot and not lay it on the bottom or you may damage it. :1drink
    #8
  9. Loadedagain

    Loadedagain making chips

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    just for fun i'll put a couple sticky thermocouples on my rads and run them through to a data logger. lets see what happens.
    #9
  10. rapiti

    rapiti IOR Veteran

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    While attempting to sort out my clutch woes, the temp light came on while the bike was idling at rest. after a minute or so, the fan hadn't come on. I have been blaming the temp light sensor for this, more than the fan sensor, or whatever trips the fan motor on.

    On a whim, I thought to open the radiator cap, after shutting her down. Steam! Spew! A bit of green AF on the floor!


    Just to recap: No clutch. No Fan. Overheating on a 50 degree day. :baldy

    I have the Evans stuff, along with the flush. Sounds like I need to look at temp. sensors. I keep have nagging thoughts of clogged galleys in the head, but the oil is always clean :dunno

    Sounds like after clutch is resolved, I have some other details to work on. :nod
    #10
  11. overlandr

    overlandr Dystopist

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    Hey Loaded, how did you go with the temp logging thing - what have you managed to uncover??
    #11
  12. rapiti

    rapiti IOR Veteran

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    That his stainless Martini glasses conduct heat better than the titanium ones he asked Santa for?? :rofl
    #12
  13. Velocibiker

    Velocibiker Adventure Antagonist

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    100 degree temps aren't that far ahead, so I'm going to add a second (right side) fan to the tanker. I've already ordered the fan and mounting it up isn't going to be much of a problem, but I'd like to snazz up how it functions instead of just an on/off switch.

    Here's what I want to do and I'm hoping one of you electrical wizzards can help me out.

    I want to add a switch that will allow me to override the LH fan and turn it on whenever I want (FAN1). Additionally, I'd like the same switch to kick on the 2nd (RH) fan (FAN2) when necessary leaving the LH fan running. Default or off switch position would return everything to it's standard set-up (FAN1 comes on based on temp). Can this even be done with a single mechanical switch?

    This STSP DTDP stuff is as confusing as Hardley Davidson bike names. :lol3


    Wiring diagram shows brown (ground) and yellow-blue (12V) running to the fan motor. Temp switch in on the ground.

    Any help would be appreciated.
    #13
  14. Gummee!

    Gummee! That's MR. Toothless

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    DI is what I'm *supposed* to be topping my reef off with... No nasty suspended particles for the algae to feed off of.

    'Course, I haven't found an inexpensive enough method of acquiring said DI, so I top off with filtered tap water. The green hair algae shows it too!

    Oh well.

    Back to the moto content:

    M
    #14
  15. txrider

    txrider Been here awhile

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    You could just use distilled water, it's deionized (DI) enough.

    Or if ya want to make your own, and really good drinking water too go get a nice little industrial Reverse Osmosis machine with a 200PSI pump on it.

    You can then run that through DI cartridges to get it to unmeasurable ppm of contaminates, but I doubt you would ever need to if the R.O. is adequately serviced.

    Pure distilled water or DI water will both dissolve metals, pure water is a very good solvent. Once you add 20% or more of antifreeze or other coolant mix the water is no longer pure though.

    As for Algea, tap water is full of it.
    #15
  16. ChrisC

    ChrisC Amal sex?

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    .
    #16
  17. AusieRob

    AusieRob Just Gas It!!

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    Yes,it is possible. But before we create a design why do you think this is a good way to do it?
    I'm doing the same mod (dual fans) to mine. My take of this is - I'm adding the dual fans to increase cooling when hot. So if the temp sensor comes on I want max cooling... So, I'm putting the 2 fans parallel across the temp sensor circuits, with (maybe) a manual override switch across the circuit as well.
    But what you ask can be done but just think about the additional wiring & complexity which equals more chance to F-up or to be F-uped...
    #17
  18. AusieRob

    AusieRob Just Gas It!!

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    [​IMG]
    Here's some ideas on how to wire as you asked. You can use relays instead etc.. The wiring shown is indicative.
    Enjoy.....
    #18
  19. Velocibiker

    Velocibiker Adventure Antagonist

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    Simply because I don't want to double the current draw all at once. I want to be pre-emptive and want to be able to kick on FAN1 at will. Then, if I see that just the one isn't cutting it (which it often doesn't), I can kick on FAN2.

    My fan normally only comes on when I'm stuck in traffic or riding slow & hard in the dirt. I can't do anything if I'm stuck in traffic, so I want the override and extra fan ability. If I'm running too hot in the dirt, there's always the option to just stop or find a less technical route to cool it back down.

    Sure. Simplest way would just be to splice the new fan into the existing fan circuit - but what fun would that be? :D

    and thanks for the diagram!!
    #19
  20. txrider

    txrider Been here awhile

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    I know my bike is a '96 and all, but the '96 thermal switch doesn't ground, it's a switch with 2 terminals.
    #20