KTM 690 enduro/SMC exhaust thread

Discussion in 'Thumpers' started by greengoose, Jul 20, 2008.

  1. dogday

    dogday Adventurer

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    You can see the gas flow in my highly tech drawing. In the other pic you can see the rear exit pipe with the flared end that slips over the bottom transfer pipe. If removed by drilling or cutting the exit pipe will slip off the transfer pipe and you'll be able to pull it straight out. Keep in mind once you have opened the thing up, any attempt to re-weld back to original will be a bit ugly. I brought a spare original muffler secondhand cheap so I could keep riding while I did the mods on my muffler.

    Attached Files:

  2. dogday

    dogday Adventurer

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    Cut away...

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  3. thetrooper08

    thetrooper08 Been here awhile

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    Great! Thanks!
  4. lightfighter

    lightfighter where does this go?

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    i did this. I made one cut and worked the cat out with brute force.... it sounded funny. but seemed to run ok. i put my LV back on.
  5. 13x

    13x Adventurer

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  6. dogday

    dogday Adventurer

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    The plan after gutting the can (see pics etc on previous page).......

    To build a muffler using the standard one keeping with the original look which I like.
    That would not produce as much heat as the standard thermo reactor muffler
    That would be lighter than standard
    That would sound better than a strangled baked bean can
    Also the original muffler body is very very strong and can take a beating because it is made of a good gauge stainless steel, I thought it might have been titanium but its not.
    To have some fun generally tinkering with the thing.

    The original plan was to make a carbon sleeve that could go over the chopped area where the two halve would butt together. Then I had the better idea of cutting a small 30mm section out of the can and weld that inside the main can with about 20mm poking out, the tail can piece could then slide securely over this and I could rivet the two parts together in the same way as most other rebuildable mufflers. This works a treat and I put the carbon sleeve over it just because i recon it looks the trick.
    I brought some 48mm (inside dia) thin wall mild steel baffle pipe. Heated and expanded one end so it would slide over the section of inlet pipe bringing the gas into the muffler. I had to put a small bend in the baffle pipe so it would line up with the inlet pipe and mig this back together Then welded a short piece of exhaust tube elbow on the tail end of the baffle pipe which then got welded to the end of the muffler. Oh yeah and drilled all the holes out oversize to allow more surface area to the baffle material. With the baffle pipe now welded to the end piece its ready for some cleaning up then some exhaust packing. I wrapped 2 meters of stainless wire around the baffle pipe then fiberglass packing. Then riveted the end on with the carbon sleeve over it, 5 rivets are plenty.

    So how does it sound??? On the throttle it was way too loud for the street for my liking so I made a DB reducer out of some of the guts I ripped out of the muffler, you can see it in one of the pics. This quiets it down about the right amount so it's not too offensive on the road, so it probably sound like a big $$ pipe with a DB killer, perhaps a bit louder.

    Heat is no longer an issue, no more risk of 3rd degree burns

    Lost some weight, not as much as I'd hope but the muffler still has it strength and looks good.

    Just a side thought, if you were looking at a new system and thought you would save some weight with a new header pipe also, I can say the stock header weighs nothing, it is amazingly light.

    This is a time consuming way to modify your muffler and it would be much easier to slap down a wad of notes on a flash harry fmf/akro/wings or the like especially if you don't have access to a mig welder and a few other handy tools. You would probably save more weight too. However if you have some time and the gear and like to tinker then go for it.

    Attached Files:

    BHedonia likes this.
  7. MeinMotorrad

    MeinMotorrad Long timer

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    What does it weigh? I weighed my original at 4.65kg. The KTM Alloy slip on with cat is 3.5kg.
  8. dogday

    dogday Adventurer

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    I got 4.7 on my standard muffler. Not a huge saving but it was one of the benefits.

    Attached Files:

  9. dogday

    dogday Adventurer

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    Here it is after a few km on the clock, Mmmmm gooooodÂ….

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  10. KC-10ENG

    KC-10ENG Been here awhile

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    Just got done re-packing my Q4 which had a similar burn mark on the canister. The Q4 has a metal disc inside the inner baffle tube in this location which is causing the exhaust to be forced into the muffler packing in this location. The result is putting a lot of heat onto the shell of the exhaust canister.

    I might try and put some bigger holes in the disk to reduce the back pressure.
  11. lightfighter

    lightfighter where does this go?

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    Dogday, I tried to make a non catalytic automotive type muffler, with moderated success... I thought about doing as you have but with an assload of packing, for a maybe quieter package? What are the odds you could just pack yours?

    Have you measured any db levels?
  12. dogday

    dogday Adventurer

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    Lightfighter, I did fill the exhaust with packing if thats what you mean. Some steel wool then the usual fiberglass matt type.
    I put as much as I could in. I don't think it quiets it down more by packing that bit extra in, it just helps it last longer. I don't know the db level but I don't like to draw undue attention to myself and I think it's not that loud that that it would piss people off. If I wanted to do that I would take the db reducer out, When I did that the other day and blipped the throttle, it caused ripples on the puddle behind the bike! Very pleasing.
    Please to be able to help if I can, seeing I now have more experience with these than I planned to have.
  13. lightfighter

    lightfighter where does this go?

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    ok... i was curious, because i wish this bike wou;d shut the hell up at times.

  14. dogday

    dogday Adventurer

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    If you find the muffler you have on is too loud you can usually pick up a mint stock one very cheap. They look good, are quiet and you won't notice any drop in power over what you have on it now. Just a suggestion.
  15. dogday

    dogday Adventurer

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    Yep looks like it needs pulling apart and a repack as a minimum. If it's new with maybe you could enquire what the warranty is after only 700k??
  16. lightfighter

    lightfighter where does this go?

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    i got a spare for the cost of mailing it to me, and saved mine. if i ever sell, there is emmissions testing in part of my market area.

    i may hack the modd'ed one open later and try a different arrangement someday if i get bored.
  17. overlandr

    overlandr Dystopist

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    [​IMG]
  18. ktm1

    ktm1 StIlL lOsT

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    Mine was a very tight fit. I just man handled it on.. And losing the strap on the wings almost all the way.
  19. gen

    gen Been here awhile

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    Thanks! I took off the gasket and the Wings did fit on perfectly. At one point I was considering high temp RTV but the experts tell me it is not needed so I didn't.
  20. webbiker

    webbiker Been here awhile

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    I have now acquired an older model stock exhaust for decatting.

    Can you mount the older model to a -14 bike simply by using only one of the two existing mounting holes on the can or does one need an adaptor?