Spark plug failure question

Discussion in 'Motorized Bicycle General Discussion' started by virginian, Aug 29, 2010.

  1. virginian

    virginian New Member

    Joined:
    Dec 19, 2009
    Messages:
    117
    Likes Received:
    0
    I started to have trouble stating my engine. It is a Tanaka 32 with 2500 miles, and it would usually start on the first try. But several times in a row it took many tries and then did not start at all,

    I replaced the spark plug and it then started just fine. Should a spark plug fail after only 2500 miles?

    Its appearance was a light brown/rust like color. No oil on it.

    However, with the new plug I lost 2 mph in speed and the engine was louder. Is that normal?

    After about 200 miles, I have regained 1 mph and the engine has quieted down. Is that normal for breaking in a new plug?
     
  2. GearNut

    GearNut Active Member

    Joined:
    Aug 19, 2009
    Messages:
    5,105
    Likes Received:
    1
    A plug can be bad right out of the box or it can last 50k miles plus.
    As for breaking in a plug, they do not need to be broken in at all.
    What do you have it gapped to?
     
  3. virginian

    virginian New Member

    Joined:
    Dec 19, 2009
    Messages:
    117
    Likes Received:
    0
    I never checked the gap. The plug was listed as the proper replacement for my engine. I assumed the gap on the plug was correct for the engine. Did I need to confirm that?
     
  4. Goat Herder

    Goat Herder Gutter Rider

    Joined:
    Apr 28, 2008
    Messages:
    6,250
    Likes Received:
    2
    As a practiced Auto Mechanic. I tell all plugs new the gap should be checked. While its true to some degree they may be gaped right. It is always good to check.
     
  5. GearNut

    GearNut Active Member

    Joined:
    Aug 19, 2009
    Messages:
    5,105
    Likes Received:
    1
    I have very rarely found a spark plug properly gaped right out of the box.
    The factories just assemble them and leave gap adjustment to the installer. Not all engines have the same requirements so the gap needs to be set to the particular engine's requirements.
    Set your plug gap to .024 - .028".
     
  6. Dan

    Dan Staff
    Staff Member

    Joined:
    May 25, 2008
    Messages:
    12,481
    Likes Received:
    49
    LOL, had a heck of a time with a HF. It ran fine but stuttered and chugged starting off. I had beaten on the clutch trying to make it fail so assumed it was that. Also didn't have peddles. Turned out it was just the gap. I'm supposed to know better but seldom do. Gap, 4 minutes of labor. Clutch 1 hr of labor and 63 bucks
     

Share This Page