Advance timing on a 2 stroke

Discussion in '2-Stroke Engines' started by 350zdrftr, May 3, 2009.

  1. 350zdrftr

    350zdrftr Member

    hello all once again. In my quest for knowledge about our addiction I have been doing some thinking. Advanceing the timing could have great benefits for these motors as far as power goes. So my question is how do you advance the timing on these 2strokes? And does anyone have any personal experience with this? Thanks to all that reply

  2. Junster

    Junster Member

    Suggest you look at the porting threads in Wild in the Streets
  3. 350zdrftr

    350zdrftr Member

    Already read all 8pages , I have not decided whether I want to port or not . Is there another way to advance timing?
  4. Junster

    Junster Member

    The only way I could think of would be to get/make a offset key for the mag. I've seen this done but not on one of these motors. You take a key that's too thick then file just the bottom part on one side till it fits the crank. Then you file the opposite side at the top till it fits the wheel. You can get as much as 1/2 a degree and be able to turn it around so you can get the offset + or - Good Luck
  5. spad4me

    spad4me Member

    I have to try this .
    A rocket key for a happytime L0L
  6. Flapdoodle

    Flapdoodle Member

    Playing with the ignition timing. Altitude here is 3700 feet, so a little advance would be nice.

    I expected it would be hard to remove the nut holding the magnet to the crankshaft, but it was slightly more than finger tight. The shaft measures .315" and the woodruff key .105"

    The circumference of the shaft is .315 x pi = .989, that divided by 360 = .0027 inches/per degree.
    The woodruff key width is about 39° and the HT is said to have 2° advance. To get 6° advance I need to offset the key about .011 inches. Not very much.

    When I installed it I tightened the crankshaft nut finger tight, then tapped the magnet with a plastic hammer to make sure it was against the new surface of the key. Now my low end torque is better and likely the gas mileage.

    Eventually I will make a true offset woodruff key.
    Last edited by a moderator: Dec 18, 2015
  7. 210061741

    210061741 Guest

    Nice post thanks for the info.

    I will lay this out in cad to verify it.

    I am planning on doing some timing advance and retard just to see the effects on my highly modifyed engine.

    I will let you guys know what i tink.
  8. augidog

    augidog Banned

    a tip, not for the guys who already know of course, but for those who haven't had the pleasure...remove the spark plug and stuff the cylinder with cotton rope, it will safely lock the crankshaft so's you can get some torque on the wrench for those tuffer jobs.

    a reminder to HT owners to check everything before you fire up.
    Last edited: Feb 23, 2010