expansion chamber questions

Discussion in 'Performance Mods' started by crlefley, Sep 28, 2008.

  1. crlefley

    crlefley New Member

    hey guys, i know that expansion chambers are designed for certian cc bikes like a 47, or whatever, i was wondering would it hurt my bike (80cc actully 69 ) chineese motor to put one of those on, or should i look for a specific chamber for my engine?

    also, anyone know where i could find a chamber to buy?

    greatly appreciated

  2. bluegoatwoods

    bluegoatwoods Well-Known Member

    I'm no authority, but here's my understanding of it:

    For an expansion chamber to work properly, it must be "tuned" to the engine. It needs to be a particular size (and likely, shape) to work with that particular engine. If you "mix and match", you're not at all likely to have something that works as well as it should.

    The rest is purely my speculation: I'm thinking that if you put a chamber on that's not right, and if the "mix" is really, really off, then you're likely to be able to tell easily. Unburnt fuel coming out the exhaust, maybe terrible performance. But maybe a "mix" that's only a little bit off will work well enough, if not perfect. I'd say it's worth a try if you have one on hand.
  3. Mountainman

    Mountainman Active Member

    bluegoatwoods has given you a fine answer to your question

    just wanted to ask
    are you truly up for the increase in noise level ???
    these things can really wiss off the neighbors and POOOLICE

    it's all in what you are looking for as we

    ride that thing MM
  4. isoxazole

    isoxazole Member

    I picked up a used Polini exhaust w/expansion chamber for $50
    It's on a polini clone motor and it screams louder now then with a HT exhaust.
  5. crlefley

    crlefley New Member

    just wanted to ask
    are you truly up for the increase in noise level ???
    these things can really wiss off the neighbors and POOOLICE

    i dont really care about the noise level, if its really that much of a pain then ill just put on the old ht motor
  6. I bought my chamber off Ebay and it was louder, so I made a new silencer and increased the internal capacity, and it is no louder than the stock muffler...
  7. Fulltimer

    Fulltimer Member

    Expansion Chamber Question

    How much louder would a bike be with an expansion chamber as opposed to a stock muffler? Does anyone have a before/after video?

  8. Fulltimer

    Fulltimer Member

    My post above was a stand alone thread. I received a warning because it was a duplicate. Then it was moved here. But, my question stands. Does anyone have a before/after video showing stock vs expansion chamber?

  9. oologah

    oologah Banned

    I have the banana shaped one from Spooky Tooth. Yes it made my exhaust really loud, rigged a muffler on the end of it and that fixed it.
  10. motorpsycho

    motorpsycho Active Member

    not of you put a baffle on the end of it, or modify the stock muffler to go over the end. My expansion chamber, with modified stock muffler gives a ton more power over the stock unmodified muffler, and my bike is no louder than your average weed eater.