TC125 falling on it's face - timing?

Discussion in '2 smokers' started by skeelo221, Aug 29, 2012.

  1. skeelo221

    skeelo221 Been here awhile

    Joined:
    May 14, 2012
    Oddometer:
    109
    Location:
    San Diego
    Hello,

    I picked up a 1972 TC125 last year that was in mint condition. It's an awesome bike and I love riding it! Sadly, I don't know much at all about 2 strokes. Here's whats happening:

    The bike falls on it's face when I give it more than 1/2 or 3/4 throttle at any RPM. It sounds like it's bogging down (like when it's running out of gas). This reaks of a carburation issue to me so I took about the carb and cleaned everything but I didn't see anything wrong (especially a clogged main). What's also strange is that it will fall on it's face in the same manner even under very slight throttle opening as the revs get above ~6k rpm indicated. Rev counter shows 9k redline I believe.

    So, it seems like it's both throttle position and RPM based. No idea what it could be other than timing which I think I would have to take into the shop cause I know nothing about setting timing.

    Any help would be appreciated!
    #1
  2. Twin-shocker

    Twin-shocker Long timer

    Joined:
    Jan 28, 2012
    Oddometer:
    1,673
    Try fitting new points and condenser, if you are 100% certain the carb is completely clean.
    #2
  3. skeelo221

    skeelo221 Been here awhile

    Joined:
    May 14, 2012
    Oddometer:
    109
    Location:
    San Diego
    Thanks for your reply!

    One more thing to add is that it happened "all of a sudden." I was riding the bike almost daily with no issues and then this started happening suddenly one day - so not like it was sitting in a barn for years and the carb had time to collect varnish.

    What tools do you need to pull the flywheel on these bikes? Is there a specific flywheel puller that you need or can you do it with standard hand tools?

    Also what should the point gap be on these motors (sorry I don't have a manual)
    #3
  4. Twin-shocker

    Twin-shocker Long timer

    Joined:
    Jan 28, 2012
    Oddometer:
    1,673
    You need a flywheel puller, and ideally an air gun to remove the flywheel nut. Without a gun you are going to need something to stop the flywheel turning, when you undo the nut with a ratchet.
    #4