Engine Trouble HT won't stay running until it warms up

Discussion in '2-Stroke Engines' started by butre, Mar 14, 2014.

  1. butre

    butre Well-Known Member

    I just got my bike all assembled again, and I'm having a really hard time getting it to start when it's cold. I have to try bumpstarting it about 35 times before it's sufficiently warmed up to stay running, and that's a serious workout on a 70 pound bike so I think I'd like to try fixing it. Once it's warmed up it pulls very strong and warm starts are reasonably easy.


    I'm thinking it might possibly be weak spark, but would like some extra heads in the mix before I go do something that doesn't help.
     

  2. FurryOnTheInside

    FurryOnTheInside Active Member

    There's a few threads (actually four at the top look good) if you put "cold starting" into the search, should be some stuff there to try.
     
  3. butre

    butre Well-Known Member

    Thanks, I see a lot of people are suggesting to richen it up, but it used to run fine with the current tune. I'll try cleaning the carb out tomorrow morning
     
  4. FurryOnTheInside

    FurryOnTheInside Active Member

    that sounds logical if it used to start fine before a rebuild. :) Hope it works for you. :)
     
  5. Fabian

    Fabian Well-Known Member

    sounds like you have air leaks.
     
  6. butre

    butre Well-Known Member

    Good thinking, I'll triple check the bolts and gaskets when daylight rolls around.
     
  7. bluegoatwoods

    bluegoatwoods Well-Known Member

    And you might as well have a look at the choke while you're at it.
     
  8. Fabian

    Fabian Well-Known Member

    A source of air leaks with the NT is the 4 slots where the clamp sits on the neck of the carburettor. Place 2 o-rings in side the carburettor and slide them up against the internal step. Bolt the carburettor in place and apply a little hand pressure to make sure the carburettor is pressed firmly against the intake pipe.

    This method will eliminate the biggest source of air leaks from the NT carburettor.

    Next, check that the top of the carburettor is properly screwed in place - this is the second source of potential air leaks.
     
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