Puch ZA50 Pull Starter (Part 1)

Installing a pull starter on mopeds is the latest trend for those who want to give up the pedal, push, or kick starts.  I've seen a lot of variations around the web on this concept.  The most popular is the use of a go-ped style pull starter with pawl.  The GS MOON pull starter and pawl combo seem to be the cheapest and easiest to use.  The pawl is connected to the moped's magneto flywheel and the pull starter is rigged onto the magneto cover or a custom bracket.  As you pull on the starter, it engages the pawl, which in-turn spins the magneto flywheel to starts the moped.  Here are a few examples:

MBK

E50

I wanted to join the pull starting club with my Puch ZA50 motor.  I searched around to see if this type of modification was done before.  But only found a video of a person starting a ZA50 motor with a belt.  This is not the kind of pull start I had in mind.  So I looked at the variations out there done on Puch E50 and Motobecane motors.  I immediately realized a problem:  Those motor's flywheel spin in a clockwise direction where as a ZA50 motor's flywheel spin in a counter-clockwise direction.  This might seem to be not a problem at first until I searched for a pull starter that rotated in a counter-clockwise direction.  I COULDN'T FIND ANY!!  No go-ped pull starters did that.  Only pull starters off old ATV bikes rotated in the counter-clockwise direction.  But they were expensive, big, and clunky for my purposes.

I went ahead and bought a GS MOON pull starter with pawl combo to see if I could do something with it.  After bringing the it to my office and staring at it for the whole day, I came up with a cheap, rinky dinky solution that works perfectly.

Reversing the rotation isn't simply just rewinding the cord in the opposite direction.  The functionality of the pull start still needs to be there.  When the cord is pulled and the unit starts rotating, the two metal rods or "catch bars" are guided along the plastic grooves and ride up to catch the pawl to rotate it.  As the cord retracts and spins in the opposite direction, the catch bars retreats down along the plastic grooves to clear the pawl when the motor is started.  The picture shows the catch bars removed from the plastic guides:

1)  Removing the center screw and disassembling the unit:

2)  Cut portions of the plastic guides and miscellaneous pieces to allow the catch bars to rotate in the opposite direction:
  

Make the new catch bar guides.  This part is important to allow the catch bar to retract back down when the unit is retracting so it won't stay snagged on the pawl.  This was actually the biggest design challenge.  Since I was staring at the unit in my office, my solution incorporates an office type material:  Paper clips.  I used paper two (2) clips for the new catch bar guides.

3)  Drill tiny holes into the unit as shown.  I used my jet drill bits for this:

4)  Carefully thread and shape the paper clips as shown.  Do not kink the paper clip cause it will cause a lose of integrity to the paper clips.  Use a hot glue gun to secure the paper clips in-place.  *UPDATE (04/02/14):  USE EPOXY INSTEAD OF HOT GLUE. *

  

5)  Use the hot glue gun to fill the old guide grooves so the catch bars won't ride up in the wrong direction.  *UPDATE (04/02/14):  USE EPOXY INSTEAD OF HOT GLUE. *

6)  The coil needs to be wound in the opposite direction.  On the opposite side of the unit, cut a new groove and wine the coil as shown:

7)  Reassemble the unit with the coil wound in the opposite direction, the cord feed in the opposite direction, and catch bars under the new paper clip guides.  Refer to this video to help you reassemble the pull starter unit.

Video of the finished pull starter:

PUCH ZA50 Pull Starter (Counter-Clockwise)

Check out Part 2 for the bike installation and performance.