Removing the EPC from a late model 640A (not a US issue)

Discussion in 'Thumpers' started by creeper, Feb 9, 2007.

  1. creeper

    creeper Still alive...

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    I was recently asked by an Australian inmate how to go about removing the EPC from his bike.

    First, a bit of information. We don't have EPCs (Electronic Power Control) in the US... and I've never seen one in person.
    I've reviewed the limited information KTM provides as well as the wire schematics enough to have a pretty good idea of how it works and how to remove it.
    I could be wrong, and if I am, I'd appreciate it if someone from a EPC fitted country could indicate where I've made my error.

    The EPC is an emissions control device that functions as a carburetor "vacuum piston damper".
    When it is engaged in the range indicated in the attached drawing, it allows atmospheric pressure in the area above the vacuum diaphragm via a solenoid valve, which has the effect of slowing down or damping the vacuum pistons response.

    [​IMG]

    As the EPC control is part of the ignition system on a late model bike, you disconnect the wires at the micro switches (49/50)... or at the connector (30), or if your feeling frisky, you can remove the wires completely by removing them from the ignition module and pulling them from the sub-harness.
    The power supply for the solenoid appears to be the starter aux. relay (42)... you can leave that in place (you kinda need it) and just disconnect the wire to the solenoid.
    Removing the solenoid assembly (44) and capping off the fitting on the top the carb is pretty much given.

    [​IMG]

    [​IMG]

    [​IMG]

    What is the possible benefit from disconnecting this system? As far as I can tell, whacking the throttle open in 2nd and 3rd gear at 45 to 55 kph is a universally popular and highly entertaining practice.
    Removing a device that restricts throttle response would insure that people the world over can have just as much fun as Americans and other nationalities that aren't hobbled by this spiffy device.

    That's about what I know... unless I'm wrong, then I guess I'm more senile than I thought. :D
    C
    #1
  2. KTMatt

    KTMatt Long timer

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    This sounds like a good thing to me. I think I might take it off and all the other shit that is just hanging of the motor that is not needed.
    Then I am going to run the breather from the carb and engine up under the speedo and put a proper filter on it. It should stop the crap getting in to the top of the the carb and doing this after 9000km.There is a lot of dust and water marks/corrsion in the top of the carb whith lots of score marks.
    The so called filter that stop rocks entering the carb now has some filter fomein it to stop the dust.

    Attached Files:

    #2
  3. creeper

    creeper Still alive...

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    I wrote a little thing on that too... filters are overkill perhaps, but my slide is clean. :wink:
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  4. KTMatt

    KTMatt Long timer

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    Thanks for the info Creeper.
    Is there anything you dont know. I think I got the water in mine from some deap creek crossing and the dust well there is plenty of that for shore this beeing the worst drought in a 100 years and all.

    Cheers Matt
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  5. rjf

    rjf SBS's #1 fan in January

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    One day I'll get around to taking it off my bike, but at the moment I just have it disabled. I did this by using a little plastic cap that blocks off the hose on top of the carb. I bought the cap from Sommer KTM when I got some other stuff from them. Apparently THere are big fines in Germany for messing with emisions stuff so that is why they block it of but leave it looking stock.
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  6. johan

    johan Been here awhile

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    Simply putting a cap on there and putting the hose aside, would that be sufficient for some testing? (i.e. could there be a problem if I leave all the electronics as it is)

    Belive it or not, but whackin the throttle in third gear at 50kph happens to be a dear hobby of mine:D

    EDIT: Just saw rjfs comment...
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  7. Odysseus

    Odysseus Stoic Philosopher

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    creeper. Solving LC4 problems the world over. :lol3
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  8. creeper

    creeper Still alive...

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    It was kind of an interesting challange trying to figure out how to disconnect a device I've never seen.
    Some folks wouldn't think twice or have an issue with disconnecting or removing it, but like anything, some folks need a little clarification.

    The older bikes (I haven't researched the cut-off point) have a separate EPC control module, independant of the ignition module... so that would be one more widget to remove and toss in the usless emissions pile.

    One of these days, maybe we can put together a "Emissions the World Over" sub-catagory in the LC4 index... kind of a one-stop-shop for emissions removal assistance. EPC, air pump, EVAP, slide stops, restrictors and anything else anyone can come up with.
    There's actually a good starting point with the thread on the SAS by Sylvia in the "Engine, Transmission, and Drivetrain" section.

    In fact... I think I'll do that now. :lol3

    C
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  9. johan

    johan Been here awhile

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    BTW, for those of you who have done this, does it give any actual improvement on the throttle response?
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  10. creeper

    creeper Still alive...

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    I'd be interested in hearing a hopefully objective impression on that myself.
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  11. jonpcovington

    jonpcovington Long timer

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    I bought a completely stock Canadian '01 Duke II that had the EPS system. I did some research and found the answer somewhere on the web, I don't remember where.

    I just pulled the wires and removed the EPS from the carb. Didn't run worth a damn, wouldn't pull off of idle.

    Then I realized that I had forgotten to plug the hole in the top of the diaphragm case.

    That done, it ran just fine, with a substantial increase in midrange oomph, as I expected. :clap
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  12. Sylvia

    Sylvia vir sapit qui pauca loqui

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  13. OzRider640

    OzRider640 SandGroper

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    Hi all.... I was said Aussie Inmate that contacted Creeper for some info on the EPC. In light of the thread/info he posted...I think we would all agree that once again ...he is "the man".
    Thanks.....:clap
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  14. creeper

    creeper Still alive...

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    I did that a few weeks ago when I installed a used 39 FCR-MX from a '03 KTM EXC on my 640A. I had yet to install the enrichner assembly ('cause I needed to modify the plunger) and started the bike with an open hole.

    Sure was hard to start with a giant vacuum leak. :lol3
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  15. rjf

    rjf SBS's #1 fan in January

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    So are we gunna see a how to convert your (03) 640 ADV from a BST to an FCR.:ear :clap

    Because My BST is getting one more float adjustment and if it still bogs its gone. Before easter too.
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  16. ChrisC

    ChrisC Amal sex?

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    Does this mean I have to excommunicate you from the cult? :pope

    I think it does....
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  17. creeper

    creeper Still alive...

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    I did take a few pics kinda after the fact, but I could write a report... to go along with the thousands of reports other people have written. :lol3
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  18. creeper

    creeper Still alive...

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    Maybe...we'll see after I get a chance to do a dirt ride. A street ride yesterday didn't really tell me too much. It wasn't better or worse... just different.
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  19. rjf

    rjf SBS's #1 fan in January

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    Yeah but the other thousands don't have that step by step, easy to follow feel to them.

    The main things I'm concerened about are

    what throttle cables to use.

    What choke cable set up to use.

    What airbox to carb rubber manifold to use.

    What carb to engine rubber manifold to use.

    How to connect the BST's TPS wires up to the FCR's sensor.
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  20. rjf

    rjf SBS's #1 fan in January

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    From the other threads and info I've read, I think I have the answers already, but it would be good to get a second opinion from Il doctore of the LC4 familia.

    (Thats you crepper, BTW)
    #20