KTM 640 SM Exhaust modification

Discussion in 'Thumpers' started by Sycamore, Apr 21, 2006.

  1. Sycamore

    Sycamore d00b

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    I need a few words on modifying a stock 2002 KTM 640 SM (yes, SM) muffler (shown pic 1 on attachment).
    I just want to open it up a little. I have tools, 2 hands, half a brain and not much money.
    I hear the groans already (not ANOTHER exhaust thread), so let me explain: I've done as much reading as I can on this forum (including the LC4 stickies), and either they are talking about some other exhaust, or there's a step that I'm missing, or some terminoilogy I don't understand. Call me dumb, that's*ok, but just help me out here.

    When I pull off the end cap at the back of the muffler, I'm faced with a solid steel plate about 2 inches down into the muffler. It has a spherical bulge in the middle, gaps around the edges, and is held in place by 3 welds at the outer edges. Almost flush against the edges of the muffler is some steel mesh. (Pic 2 on attachment).

    What is this plate and what do I do with it? Is it a spark-arrestor? If so, should it be removed? Cut or grind through the 3 mounting points or welds? Would drilling holes in it do anything?
    Knowing this would at leat get me started, any further info would be welcome.

    TO AVOID BOGGING DOWN THE FORUM WITH ANOTHER ZORST THREAD, anyone who has done this procedure is welcome to email me at katoombah@yahoo.com so I can ask questions direct. I'll be very brief and wont spam you, promise.

    Thanks all.
    #1
  2. dagwood

    dagwood Banned

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    whow, never seen one like that before. it should have a flange with a hole in it. on the flange there should be a 6 bolt pattern for the Supertrapp disc's to mount to. this looks like someone cut it out alltogether and welded in a plate.
    Are you the first owner?
    other than looking on Ebay for a supertrapp or other used Lc4/SXC pipe I don't know what to tell you.
    sorry, good luck.
    #2
  3. meat popsicle

    meat popsicle Ignostic

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    The outside looks like the same Supercrapp that I have, but inside you have a welded on bit instead of a bolted on stack of discs and endcap... not adjustable. Bummer! I don't know what lies directly beneath that welded on cap (someone here might; wait for it).
    #3
  4. motophil

    motophil Paint it black!

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    It's the standard LC4 exhaust named HGS4 (engraved on it somewhere), as it is stock on all (European?) 640 LC4 since 1998. But I guess some US LC4 come with a supertrapp can.

    - Philip
    #4
  5. Sycamore

    Sycamore d00b

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    No, I'm the second owner.

    But the guy I bought it from was the first owner - he claims he never touched thing on the bike, and I have reason to believe him.

    It's totally stock, even has the "Read the Maual Before Riding this Motorcycle" sticker still on the fender. By the way the exhaust also has a catalytic converter on it, halfway betrween muffler and header.

    This is a mystery, maybe mine is different to the US models?
    #5
  6. Sycamore

    Sycamore d00b

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    ok, now I know what it is... next question is, how to open it up?
    #6
  7. Sycamore

    Sycamore d00b

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    Maybe the cap is welded there to stop naughty children from making the exhust louder? (We know what the Europeans are like). Perhaps the supertrapp discs lie benenath?
    For the benefit of ADVrider I'm willing to cut the cap away & see what's underneath, but I'd require a new Supertrapp as payment for my service to the forum.
    #7
  8. ChrisC

    ChrisC Amal sex?

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    That's assuming that anyone here gives a shit what's inside.... :eek1
    #8
  9. meat popsicle

    meat popsicle Ignostic

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    Ignore ChrisC, he is awfully crotchety this early in the AM... :lol3

    I have a stock Supercrapp wasting space in my garage, but it wouldn't be worth the freight to ship it to Dubai. It weights about 16lbs.!

    Why not buy an aftermarket can? The one I am currently looking at is the Staintune. Completely mechanical baffles, so there is zero maintenance. They list for a bit over $200 in the USA. You can get their full exhaust for around $600. Folks seem to love them. Staintune is Australian.
    #9
  10. Sycamore

    Sycamore d00b

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    I'm planning on getting an aftermarket piece, but it's gonna have to wait a few months, the cost of this bike plus insurance etc nearly killed me. So I'm looking for more of a temporary fix, this muffler sounds pathetic and is really restricted.

    I heard good reports about Staintune, but dealers here are limited, and often not willing to ship in a single unit.

    Speaking of Supercrapp, I heard A-crap-ovic is also good.

    Hey, anybody else out there know what to do with this exhaust? Come on!
    #10
  11. ChrisC

    ChrisC Amal sex?

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    Hey! it's Friday, it's gonna be 80+ F here in N. Colorado tomorrow and I'm going riding.... who could be crotchety with that on their plate?

    But I still don't give 1/2 a shit what's inside a "Dubai-Can".... :D
    #11
  12. meat popsicle

    meat popsicle Ignostic

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    Karma baby, watch your karma... :eek1

    That can is the Euro version of the Supercrapp, so it matters to most of KTM's market! I was thinking that there is no way KTM would ship that POS stocker back to Europe from the USA and simply used a Euro can for those bikes.

    But on second thought the Supercrapps are probably made in China... so it really isn't all that surprising that they have the same anchor we do. Just a regulatory difference probably (adjustable vs. piss off! models).
    #12
  13. ChrisC

    ChrisC Amal sex?

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    You Karma, I say Kharma... let's call the whole thing off...

    I went out and looked at mine (hanging from the rafters in the garage) in it is stamped "Made in Dubai".... :lol3
    #13
  14. rjf

    rjf SBS's #1 fan in January

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    Why not contact staintune directly and see what the cost is for the to ship it to you. I think any prices you see on the web site will include GST ( goods and services tax), our equvalent of VAT, which you might not be charged as your getting it sent out of Australia. I'm not 100% sure though.

    http://www.staintune.com.au/

    http://http://www.staintune.com.au/contact.htm

    <TABLE cellSpacing=0 cols=2 cellPadding=0 width="100%" border=0><TBODY><TR><TD vAlign=top width=12 background=images/bg/bkg_dots.gif></TD><TD width="98%">[SIZE=+2]Staintune Australia Contact Information[/SIZE]
    STAINTUNE: Australia's Pipes of Perfection
    <TABLE cellSpacing=0 cols=2 cellPadding=0 width="90%" border=0><TBODY><TR><TD vAlign=top align=left>Phone (02) 4871 3188
    International 612 4871 3188
    Fax 02 4871 3581
    Staintune Australia
    51 Cavendish Street
    Mittagong NSW 2575 Australia</TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE>
    #14
  15. ChrisC

    ChrisC Amal sex?

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    Hey RJ, do the Staintune cans come with spark arrestors?
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  16. neepuk

    neepuk Such a drag...

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    I say you should just drill a big hole right in the middle of the plate and look through, see what's inside. Your going to replace it in the future anyway and you are looking for better flow. Just go for it IMO. Keep us posted.
    #16
  17. rjf

    rjf SBS's #1 fan in January

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    Whats a spark arrestor ?:lol3

    Nup, like the letter from them states we don't have a requirement for them here, I think Spark arrestor's are unique to USA.

    The staintune does come with a removable plug in the outlet though.

    [​IMG]

    http://http://www.staintune.com.au/faq4.htm

    If a spark aresstor is a peice of mesh ( anyone care to post a pic of one for me) you could easily fit one.
    #17
  18. ChrisC

    ChrisC Amal sex?

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    That's what I figured. Big Brother here requires the can to be stamped with USFS (Forestry Service) approval. :cry
    #18
  19. meat popsicle

    meat popsicle Ignostic

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    I just posted some info (from Staintune and a US importer) regarding a sparkie - not from them and I know of no aftermarket add on (with USFS stamp of course). The insert rjf pointed out is a dB eater that looks like it could become a sparkie easily... but you still need the USFS stamp. Anyone know if one of the aftermarket sparkies might be close to fitting? perhaps an adaptor could be made by Loaded (I'll volunteer him :lol3) or on www.emachineshop.com if he refuses? :ear

    Check the LC4 exhaust thread for my post.
    #19
  20. rjf

    rjf SBS's #1 fan in January

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    Down here when the road registerable bikes have a code stamped on the silencer, which must correspond to the noise test info sticker on the frame. The police were booking people with stock, unmodified mufflers if they didn't have the sticker on the bike. :eek1 :deal .

    A motoorcycle lobby group managed to get some indipendent Politicians to bring the issue up in parliment. now the police cannot book people for not having the sticker. My KTM, and every other one I've looked at don't have the sticker anyway. My R1 and every Japanese bike I've checked has though :dunno

    I'm all for bikes needing to have quiet mufflers, helps keep riding area's open IMO.
    #20