Installing a fan on the 625 SXC

Discussion in 'Thumpers' started by crazybrit, Feb 4, 2007.

  1. crazybrit

    crazybrit Long timer

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    I just did this, thought I'd post some pics though it's definately not rocket science. It does save you about $100 however.

    The DIY parts list is as follows:

    1. Fan Flap 58435044050 x2 @$3.48
    2. Fan Screw 0081500181 x4 @$.81
    3. Fan Shroud Screw 0017060203 x2 @$1.08
    4. Protector 58312085100 1 length $7.55
    5. Fan 58435041000 $85.68
    6. Fan Shroud/Cap 58435044000 $15.12
    7. Thermoswitch: 58435045098 $34.67
    8. Fan wiring harness: 58311079100 $26.72

    This is however the expensive way to go.

    There was a kit 58335141044 (for the 2001 SC) which is no longer available. The main difference from above was that it used a 14mmx1.5 thermoswitch with an opening temperature of 80-85C rather than #7 58435045098 above (see: 660 SMC fiche) which is an 18mm and has an opening temp of 98C. I believe the Adventure uses the 98C switch.

    Also it's worth noting that the fan wiring harness and thermoswitch are a matched pair. #7/#8 above use a moulded style connector (2003 and newer bikes). The wiring harness and thermoswitch in the discontinued kit use spade terminals.

    After some sleuthing I found that the current hardparts fan kit for the 525 (59035041044 - shown on the "COOLING SYSTEM 450/525 SX RACING" fiche) is the same as the discontinued kit except for the fan shroud. It's also even cheaper @$98 list. The discontinued kit used the LC4 shroud (58435044000). This hartparts kit uses #59035044000. Wageslave posted some excellent pics of the difference between the two fan shrouds in his "2nd fan for the Adventure post".

    It's slightly more work to use the 525 kit rather than the individual parts but it saves well over $60 and you get a fan which kicks in at a slightly lower temperature which is fiine with me since like the 525, the SXC doesn't carry a lot of oil. If you want 100% plug-n-play you'll have to buy the 8 parts individually and the fan will kick in at the higher temp.

    Anyways, some pics:

    #1 I don't have good pics of this step but:
    - drain the coolant
    - remove the 18mm plug (#32 on the SXC cooling fiche) from the lower right side radiator. Drill and tap it to 14mm (1.5 pitch). Have a machinist do this if you don't have a drill press. Warning: you will need a very steady hand and sense of level to do it freehand.

    #2 Install the thermoswitch. It'll end up looking like this. You can see the old tapped plug to the right of the aluminum washer. You can also see the spade terminals.

    [​IMG]

    #3 reinstall the coolant (either saved from before or new at a 40/60 coolant/water ratio), capacity for the SXC is 1 litre (assuming you drained the motor as well as the rads). Make sure all the hoses are tight (but don't over tighten, you can put some serious torque in if you use a 6mm socket). Fire up the bike, check for leaks and bleed any air out of the cooling system. Owners manual contains the procedure for fine tuning that the level is correct.

    #4 Installing the wiring:

    Here is a pic of the wiring harness that comes with the kit:
    [​IMG]

    #5. Mount the fan.
    I chose to mount it on the left side. You could mount it on the right side but you'll have to do some minor relocation of the capacitor. Another good reason to mount it on the left side is that the holes on the left edge of the fan shroud line up exactly with the radiator mounting holes (the fan flap should be on the top). The holes on the right side of the shroud are different spacing.

    Here are a couple of pics of the fan ziptied in place:

    [​IMG]

    [​IMG]

    The inner radiator mount for the left side radiator is going to prevent you from mounting the fan in any closer:

    [​IMG]

    Trim away a little material from the right side of the fan shroud to clear the bolt (take as little away as possible to maintain the structure of the shroud as the bike does vibrate a bit :D). You can see also here how the holes on the right side of the shroud are not compatible with the radiator mounting holes:
    [​IMG]

    You may also have to rotate some radiator hoses to make the fan clear. If you have the 18l (or IMS) tanks installed it looks like it won't clear the tank bumpers but it will. Here is a pic of it all mounted up, using the two screws which come with the kit, stock mounting holes in the radiators and the fan shroud:

    [​IMG]

    Here is a pic of the wiring on all connected on the right hand side. Again, if you have a larger tank you'll have to do some tidying of the wiring to make sure the tank can contact the bumper rubber without catching any wiring. I ended up routing the wiring between the capacitor and the radiator but don't have a final pic:
    [​IMG]

    Thats it. Put the tank back on, start it up and wait for the fan to start up. It'll take a while but you'll hear it when it starts, even over the clatter of the motor.l
    #1
  2. creeper

    creeper Still alive...

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    Very nice write-up CB... I'm sure it will be a benefit to those looking cool down their 625 SXCs and similar earlier models with no fan.

    C
    #2
  3. meat popsicle

    meat popsicle Ignostic

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    How does this caliber of work slip thru the cracks?!? Oh yeah, I was sloggin' thru the bottomlands of TN at the time.

    Give it up for crazybrit :freaky

    Nice work, probably be the first SXC-specific how-to in the index...
    #3
  4. sinuhexavier

    sinuhexavier Adventurer

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    Just did this today.

    Thank you for the great step by step and photos.
    #4
  5. Cruiser

    Cruiser Cruiser.. 16 beta 350rr, 04 KTM 525sx/exc FS

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    just installed one on my 03,, it was hard to find the hookup on the bike for the fan,, they hid it very well at the factory. I did not install the switch in the kit on mine as the right rad was just replaced with a NOS for an ADV 640 and had a switch in it. The temp stamped in the switch was 85 on both the switch in the kit and the one on the bike.. so I didnt want to change out and loose the coolant I just put in.. Now if I only remembered the rad cap when I was at the shop picking everything else up.. :huh
    #5
  6. Cruiser

    Cruiser Cruiser.. 16 beta 350rr, 04 KTM 525sx/exc FS

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    Just an update,, rode some tight stuff today,, fan worked awsome!!
    #6
  7. gladiator

    gladiator Adventurer

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    Right, a question for you 640 guru's. I have recently replaced a cylinder head gasket on my '07 ADV, and before disassembly the coolant temp. bar graph was working perfectly. Now, after assembly, i have no reading on the bar graph although the fan kicks in at the right temp. I have inspected all of the wiring and nothing looks dodgy. The wires that coming from the temp. sender unit seem to go to the electronic rev counter, WTF? Can anyone shed some light on this problem. When i turn the ignition key on, the temp, bar graph comes on, so i pressume the display is working correctly, it does not seem to be getting any signal from the sensor.
    #7
  8. MNCherryinCA

    MNCherryinCA KTM Noob

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    Hi All,
    I finally got the electricl right on my fan and it is working. however, it seems like it is SO HOT (98C or something) when the thermoswitch closes, that it's almost too late to cool down the coolant with the fan.

    I am kind of resorting to shutting the engine off if I am at a stoplight or stopped for another reason, where I would otherwise let her idle.

    Anyone know of a better way? (other than a bigger radiator or new bike)
    #8
  9. crazybrit

    crazybrit Long timer

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    did you read the first post???????????
    #9
  10. MNCherryinCA

    MNCherryinCA KTM Noob

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    yep...I did a while ago. I think I forgot due to me not wanting to machine a different size plug.

    How did you put a 14mm plug into the 18mm hole in the radiator? Did you drill and tap the actual plug that was there? I think I am screwed as I don't have the plug anymore. I guess I could buy a new plug and then drill and tap.
    #10
  11. crazybrit

    crazybrit Long timer

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    Again, described in 1st post.
    #11
  12. MNCherryinCA

    MNCherryinCA KTM Noob

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    yep..right on...
    #12
  13. timg

    timg Adventurer

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    Hi Folks,

    I'm installing fans on my 625 SXC. Given that I'm using this to commute in town as well as my Adventure bike I thought I'd stick a fan on each radiator. However I have a gizmo on the right side of the engine that is not in your photos. What is it? It's in the way of the right side fan :scratch or where it would be. Thanks
    [​IMG]
    And a picture of my 625 SXC 'Adenture' :D
    [​IMG]
    #13
  14. Tseta

    Tseta Lost

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    timg: That's the SAS (/SAI) emissions "crap". You could (and probably should) remove it, some details in this thread.

    I assume you are familiar with the LC4 Index Thread! already, it contains many useful links to most common issues and questions about the LC4.

    Cheers,

    Tseta
    #14
  15. meat popsicle

    meat popsicle Ignostic

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    One note on this mod: if you rear subframe is off-center at all (meaning bent) then you might have a problem with it. My subframe is bent, which puts the tank off-center and reduces the space available for the radiator fans. I installed the second only to find it contacted and rubbed on the tank. If I had been hit on the other side of the bike then the first fan would probably be hitting and I would have had to move it to the other side (or straighten the subframe... :)
    #15
  16. timg

    timg Adventurer

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    Thanks guys :clap much appreciated. Cheers, Tim
    #16
  17. nochain

    nochain Adventurer

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    Was looking into this and wondering if the stator can handle a fan on my bike. I think not from what I heard but I don't know the limit or spec.

    I have a 2003 SXC625 LC4

    Thoughts?
    #17
  18. gunnerbuck

    gunnerbuck Island Hopper

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    l

    The stator will have no problem handling a fan or 2 and you'll still have power to spare...
    #18
  19. Cruiser

    Cruiser Cruiser.. 16 beta 350rr, 04 KTM 525sx/exc FS

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    The 625 has plenty for a fan.. I ran a fan and twin lights on mine. no issue at all.. now I wouldnt try to go put heated grips and a heated suit onto that as well as the other stuff.. but you may be able too.. The smaller RFS is fine with the fan and lighting tho it can be taxing at times. The RFS needs to be upped to the 100w DC system to put out enough.. The SXC has a three phase system already that even tho its not big by street bike standards its huge by dirt bike standards.. I think its 180W? Fan and lights are no big deal with this system.. unless your running twin 8" racelights and other stuff.. I was running twin 4" lights I fabbed up to test out. they worked fine. No issues. Just ugly as hell and kept stock on it until I sold it. I was planning to go to buell twins lights or hella modules like the 640's had..
    #19
  20. nochain

    nochain Adventurer

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    Thanks Cruiser now to look for a 4in fan ....
    #20