Muffler port does not match?

Discussion in '2-Stroke Engines' started by Dice1, Jul 8, 2011.

  1. Dice1

    Dice1 New Member

    Why is the port on the head not match the mounting of the muffler? i got extra gaskets that look like they would match the head better but then the muffle wont match.

  2. Al.Fisherman

    Al.Fisherman Active Member

    Are you sure you are trying to mount the muffler to the exhaust port and not the intake port. Both studs have different measurements? I'm assuming you are talking about a Chinese in frame engine. Have you taken the cylinder off and installed it backwards? Installed the intake port points directly aft and the exhaust points at a 11:00 position while sitting on the bike.
    Last edited: Jul 8, 2011
  3. Dice1

    Dice1 New Member

    Yep its the right port. Just the flange on the exhaust is round and the head is like a ovaled rectangle like on big block chevys. It runs fine just thinking that like a regular car the ports make a big difference in the smooth flow of the air.
  4. motorpsycho

    motorpsycho Active Member

    that's just the way they're made, but you can port the exhaust and gasket match the port.
    by the way, not all big block chevy engines had rectangular exhaust ports.
    the high performance and marine heads have rectangular exhaust ports, and the truck, standard passenger big blocks had oval exhaust ports ports.
    the oval port heads were more for low end torque, and the rectangular port heads were more for top end rpm's.
    the rectaungular port heads flowed more than the oval port heads.
  5. HeadSmess

    HeadSmess Well-Known Member

    cus theyre cheap and well, what do you expect? high precision fits on each and every component? look at the flange! its a piece of punched plate barely tack welded to a pipe... and the pipe is narrower than the port!

    the ports horrible, anyway. really needs filling in til it actually is round, 18mm or so diameter. if you really want to go chasing horsepower, without affecting exhaust port timing...
  6. blue 48

    blue 48 Member

    :thinking:so is it possible to with a decent manifold and pipe match the port? (say18/19mm)
  7. cloud_2901

    cloud_2901 Member

    Saw some really cool laser-cut inlet manifolds for sale on a thread on this site, but that was late 2010, I'm actually interested if they are still around too. . .

    Pipe-wise, get a dremel and someone with a steady hand?
  8. blue 48

    blue 48 Member

    im gonna make a pipe and stuff myself time permitting