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Custom adjustable exhaust

Discussion in 'Modifications and Projects' at netrider.net.au started by jones88, Oct 5, 2010.

  1. Hey guys, hope i'm posting in the right spot.. :-s

    I'm looking at doing a bit of custom work to my exhaust, but just wanted to get some input before i decide on my final plan.

    Basically i want to be able to change the sound of my bike easily.

    I have looked at the Jekill and Hyde systems for harleys, and i'm kind of thinking it would be a bit expensive.

    Unfortunately i'm unable to just get a slip on for my bike, so a little bit of custom work is near enough the only option.
    What i was thinking was to have a straight through pipe with an adjustable muffler on it (telescopic style) so that i can shorten and lengthen it. I would then be able to move it so that the pipe finished at the start, 1/4 1/2, 3/4 and the end of the muffler.

    My main question is, would this be legal?
    would it make enough of a difference sound wise?
    Any drawbacks for power?
    Most importantly, has it been done? I'd love to see it.
  2. A universal fitment Supertrapp would be a whole lot less work and are, at least, a known quantity.
  3. to the best of my knowledge the tip of the exhaust must "vent" at a minimum distance behind the rider, which is why most exhausts you see go behind the rear wheel. Even Harleys with straight pipes all vent behind the rider. So they don't make these pipes this long for sound, its for legal reasons (similar to why your car exhaust must vent behind your car).

    As long as your pipe meets this requirement, and is under the decibel limit, I believe pretty much anything goes.

    The length of the actual pipe between the engine exhaust and the start of the muffler will have little effect on the note/tone/sound. What effects the sound is...
    a) the length of the muffler (certain lengths will cancel certain frequencies better)
    b) the structure of the muffler (e.g. baffles, tuned sound box)
    c) the materials of the muffler/sound absorbing material (wire mess, fibreglass etc)
  4. Thanks, that's something I totally forgot to consider. So I will have to find out how far the minimum distance so I know how much play room I have.

    I am more think if the muffler itself is adjustable, it will increase/decrease how far up the pipe it is. This would mean the sounds will be more/less filtered through. That's my assumption anyway. :p

    I should have mentioned to, this is for a vfr 750, 1990 model.