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749 The Dreaded De-cat Pipe

Discussion in '749 / 999' started by Mongoose, Sep 5, 2015.

  1. So,I'm trying to get this de-cat link pipe to fit my bike but it don't wanna go. Well,almost don't wanna go. The problem I'm having is its just kissing the bottom of the sump by the oil filter. Also the bracket that supports the rubber fairing stay has been welded on the wrong way. The bracket doesn't bother me to much as I can quite easily modify it to do the job but it's where it's touching the sump that's a little concerning. I'm thinking of flattening the pipe slightly where it's touching but if I do this and it doesn't work then I'm stuck with a bent up pipe which will then become non returnable. This pipe is from a 999. I have a 749 but as far as I'm aware they should be the same unless anyone knows different?
    Basically my question is

    1 Do I have a shallow sump motor in which case this pipe should fit?
    2 Do I have my original pipe de-catted?
    3 Does de-catting really make a difference?
    4 Should I really be doing any of this this at all as I've nearly skinned both knuckles already?
    image.jpg image.jpg
    Thanks in advance for any helpful information on the situation.

    Mongoose
     
  2. I'm no expert on this but red frame suggests deep sump to me or it would for a 999 anyway.
     
  3. That's a 749 so shallow sump only (apart from R).
     
  4. the picture tells us that it is a shallow sump ( despite the colour of the frame :Banghead: ),, but,, the 749 carries a 54 mm termi, whereas some ( maybe all, i dont know ) 999 have a 57mm termi,,, maybe that is your problem,, measure internal diameter of pipe at manifold... ( i am no expert )
     
  5. #5 chrisw, Sep 6, 2015
    Last edited: Sep 6, 2015
  6. The header diameter is not related to the model. Many 749R's have a 57mm system and I have seen plenty of 999's with a 54mm system. Plus a 54 or 57mm system means a full exhaust, the slip-on has different header diameters due to the difference in length as well.
     
  7. you maybe right mate,, but i have heard / read that 749 only has 54mm........... now i want a 57mm,,,,,,,, if poss !!:confused:
     
  8. 749R will take a 57mm but 749BP or 749S loses power with such a big pipe attached, be happy with your 54mm.
     
  9. Phew !!!!!! Thank you ....
     
  10. Have you also changed the silencer as the cat for the rear cylinder is in there . Ones no good without the other so i believe .
     
  11. :upyeah::upyeah::upyeah:;););)
    Yes. I've fitted a Termi 'Slip on' muffler so I beleive I have to now replace the horizontal link pipe with a 'cat free' one. This is the correct pipe for a shallow sump bike (see previous quote thanks @chrisw ) which I now know I have. The darn thing is it's only just kissing the bottom of the sump near where the oil filter lives which is kinda concerning me.
    The way I see it is I now have three options

    1 Stop fannying about with it and flatten the touching part with a sledge hammer (number one choice so far)

    2 Have my original one cut open and removed and re-welded ( not to keen as I've already bought a de-cat link pipe to prevent this)

    3 Say bollox to the whole thing and run the bike with just one cat ( properly won't do this but it's an idea I suppose )


    I welcome any advice with open arms and ears ;)
     
    • Like Like x 1
  12. It sounds to me as though you're trying to fit a pipe from a pre-facelift bike to your later model. If it came off a Grey swing arm bike it won't fit a Black swing arm bike.
     
  13. You could always cut in half through the cat remove the cat and get it welded back together as you have already said. This would be my method.
     
  14. What difference does de-catting make ?
     
  15. Improves gas flow -> 'more power' -> more noise -> less heat -> win.
     
  16. In the pipe nothing. In the muffler, cooler but bugger all power.
     
  17. Hi Can you change the oil filter with this set up ?
     
  18. Wow your the man for digging up some old threads !:cool:
     
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