Expansion Chamber blockage fix? (stock exhaust)

Discussion in 'Exhaust' started by Jeff C, Nov 12, 2021.

  1. Jeff C

    Jeff C Member

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    I have a severe blockage in my stock expansion chamber.

    I recently replaced an aftermarket exhaust on my good running 91 Blaster with a used stock exhaust. Bike became difficult to start and would not rev above idle, even when the muffler was removed. There didnt seem to be any exhaust flow out the tail end. After I removed the expansion chamber, the bike started and revved easily, but was loud as hell.

    I blew out the expansion chamber several times with compressed air in reverse direction and got some fiberglass and straw, but the problem is still there...

    Has anyone else seen this or know of any fix? I assume I will have to cut open the chamber to fix this, does anyone know if there are baffles inside and where they are?

    Thanks!
    Jeff in Colorado
     
  2. Jeff C

    Jeff C Member

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    I just found the posts about the stock exhaust internal cone and sound deadening. Based on all the evidence so far, my guess is that the expansion chamber sat for some time, and a mouse family nested inside it, using straw and pink house insulation to make a nest.
     
  3. Deets

    Deets Member

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    You could try burning it out with a propane weed burner?
     
  4. Jeff C

    Jeff C Member

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    sounds kinda scary to me...
     
  5. Deets

    Deets Member

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    Scary?
    Google how to remove dents from a 2 stroke pipe.
     
  6. Deets

    Deets Member

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    Sorry, not dent removal. Pipe cleaning or de carboning
     
  7. Larry's Shee

    Larry's Shee Active Member Technician

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    Only problem is fiberglass doesn’t burn. Straighten a metal coat hanger and go in from engine side. Small hook to grab stuff
     
  8. Jeff C

    Jeff C Member

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    Thanks for the suggestions, guys.

    I borescoped the pipe yesterday without success - the borescope was not flexible enough or long enough to make the turns in the inlet side of the pipe. I dont have the equipment for the propane burner approach and the fiberglass is not likely to burn. I will try the coat hanger approach today, followed by reverse flowing water thru the pipe. Plan B is cut the pipe open.

    Jeff in Colorado
     
  9. Jeff C

    Jeff C Member

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    Guys,
    Trying to get the internal junk out of the pipe was hopeless with the coat hanger because of the many bends in the inlet side.


    But the water reverse flush worked well. After several flows thru the exhaust end of the pipe which flushed some leaves and fiberglass, the pipe plugged up solid. I kept the water pressure on, and eventually a nest of straw and fiberglass extruded out the inlet of the pipe and blew out. The nest was the size of a softball! Several more flushes came out clean. Will test run tomorrow.

    Jeff in Colorado
     
  10. Jeff C

    Jeff C Member

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    Everyone- Water blowout worked perfect. Bike runs fine now!

    Jeff in Colorado
     
  11. Deets

    Deets Member

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    Glad to hear, lot easier than burning too.
     
  12. Larry's Shee

    Larry's Shee Active Member Technician

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    Good job !!
     

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