Exhaust My Murphy McMonkeyPatcher diy exhaust replacement - effective, ghetto AF, expansion chamber exhaust

Discussion in '2-Stroke Engines' started by Nate888, Sep 30, 2016.

  1. Nate888

    Nate888 Member

    originally I had the voodoo brand I think of banana tube expansion chamber that came w/ the kit I ordered (IIRC i talked the guy into throwing it in cuz I got a aluminium gt frame kit plus a relatively premium engine kit at the same time) but I had problems w/ it not quite fitting, then when i bent it around the frame for a proper fit I was a bit careless & cracked it & didn't mount it quite well enough.... it actually sheared right off where it curves around the frame & left me w/ about 6in straight pipe.

    straight pipe ==> runs like crap, maybe 1/2 power, plus it sounds like an F'ing ammo dump burning down

    I bought a cheap stock exhaust used on some MB's from a friend for $10, but it's so restrictive at the end that power's no better than the straight pipe (though noise sure is). It's pictured in the attachment

    anyway, long story short, I took matters into my own hands & made this somewhat frightful expansion chamber exhaust. I made the main chamber part by cutting out the inside of a can of spray paint, putting it over the broken straight pipe, & bending it into the geometry I wanted as best I could. it's held in place w/ some wire & cable; a few layers of foil & muffler repair cold weld adhesive putty; and a little duct tape & hi temp engine paint. Also, there's a second aluminum bottle cut open & nestled on over the expansion chamber (steel paint can)'s outlet, w/ a tiny bit of foil & steel wool for sound dampening in the between space

    I didn't really expect it to work, but now that I sealed the leaks it's giving me better performance than the often $70+ (or unavailable out of stock) voodoo expansion chamber I had originally had. power seems boosted in mid range & higher engine speed

    conveniently, there's a radar speed camera on a challenging uphill by my house, so I can charge the hill & use it to gauge power output. results have been:

    • badly out of tune, or >50% choke -- won't make it up.
    • voodoo banana expansion chamber exhaust -- 24mph
    • Straight pipe -- 17mph (& lucky not to be arrested for disturbing the peace!)
    • Stock lo end replacement exhaust -- 18mph
    • Murphy McMonkeyPatcher kludge pictured below - 26mph!!
    20160930_105501.jpg 20160930_105456.jpg

    Clearly, the right way to do exhaust modding involves learning to weld. but I'm finding it possible to get surprisingly acceptable results w/out access to welding equipment.

    Any thoughts, tips or experiences you'd wanna share on this?

    Attached Files:

    Last edited: Sep 30, 2016
    zippinaround likes this.

  2. Nate888

    Nate888 Member

    I've also been wondering if there's any kind of craft or construction product - some kind of clay, or structural concrete repair compound perhaps - that would be useful for forming & sealing homebrew exhaust setups. Anybody tried anything along those lines? muffler repair putty is kinda pricey, so if there's a cheaper option, I'm interested
  3. Arty

    Arty Active Member

    It's so ugly I love it!
    Nate888 and zippinaround like this.
  4. Nate888

    Nate888 Member

    so ugly it's almost beautiful, like an ocean sunfish or a narwhal? :p
  5. zippinaround

    zippinaround Active Member

    i just love when things get creative! do you drive it with the chain like that? tensioned up on itself?
  6. Nate888

    Nate888 Member

    you mean the motor drive chain? yea the chain tensioner holds it where it looks like it's almost gonna hit itself, but it seems to be good when actually driving it
    zippinaround likes this.
  7. Neptunati

    Neptunati New Member

    Dear sweet sweet baby Lord Jesus. Just wow. I may have to send you a proper exhaust.‚úČ
  8. Steve Best

    Steve Best Active Member

    I was thinking skate, sculpin, lamprey or wolf fish...

    Muffler cement of course, its main ingredient is Sodium Silicate or "waterglass" which is a water soluble, heat hardening compound used in food industry and a lot of things. It is used for glueing the fiberglass gaskets to the doors of woodstoves and can be bought at a woodstove store. It was also used to destroy engines in the Gov't junker buyback program. Pour it in a running engine's oil and watch it seize up.
    Last edited: Oct 22, 2016 at 7:47 AM
  9. Timbone

    Timbone Active Member

    No. Just no.
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