HELP: I believe I have an Exhaust Leak, but not sure

Discussion in '4-Stroke Engines' started by AnvilBlockForge, Mar 29, 2013.

  1. jaguar

    jaguar Well-Known Member

    An exhaust leak won't change how it runs. You have to use starter spray until it warms up which means there is either an intake or crankcase leak or the jetting is too lean.
  2. No, the motor runs fine, I'm concerned with the loudness. Is this the way the bike should sound after a new exhaust? It sounds the same as the original exhaust. I have to use carb spray because I am in the process of constructing a gas tank, so there's no gas supply. But I wanted to have it run to see if y'all expect or hear a exhaust leak, or is that how its suppose to sound?
    Last edited: Mar 29, 2013
  3. jaguar

    jaguar Well-Known Member

    What did you expect it to sound like? The original exhaust was a header with muffler. The new exhaust is a header with two mufflers.
    It's hard to hear what you are hearing when we aren't there in person.
  4. The original exhaust was just that stubby "can" exhaust that comes stock on tillers. And it was rusted threw and shot flames out. And after I fabbed this up, it sounds no different. But when it idles, it has a nice putter. I expected it to not sound the same as it did with the rusted muffler on it

    It sounds the same as it did when it had this muffler on, except when it is idling
    sHOP 039.jpg
  5. jaguar

    jaguar Well-Known Member

    You could try eliminating one of the two mufflers to increase outlet restriction which decreases noise.
    The general tendency is to believe that more restriction decreases engine power but that is not quite the case. A certain amount of restriction is needed for back pressure which restricts loss of intake charge out the exhaust port when the piston is rising. So at the sweet spot you have less noise and more power (especially at low rpm).
  6. Yea, alot of people get on to me for the 90 degree angles, but I also agree on these small motors a little back pressure helps. But I wasn't aware it will affect the sound. Thanks! I'll see if plugging a muffler makes a difference, if it does, I shall remove it. Thanks for the idea!
  7. I found the leak, it was leaking where the header attaches to the block, the bottom of the gasket tore out and had fallen off leaving a gap. So I purchased another gasket and now it sounds great! Has a nice putter to it.