Puch ZA50 Clutch Installation Tool

Getting springs on a Puch ZA50 stock clutch isn't a walk in the park.  Many of us shy away from cutting or reinstalling new springs onto our clutches because of the difficulty and hassle to get them on.  But by doing either spring modification, it can greatly benefit a ZA50 motor's performance.  For a long time, I've been thinking of a way to easily reinstall springs onto these clutches.  I've been looking for a better way ever since I ruined the elasticity of my first springs by installing them with a bunch of screwdrivers.  In the past, we used a D-sized MagLite flashlights or a worn down skateboard wheel to get them on. But these methods usually meant more than one pair of hands to do it.  I've even saw someone use their bare hands to get them on.  Ouch!!  I just don't have that kind of hands!!  With a design in mind I had for years, I finally decided to try to make life easier for all us ZA50 modders:

A very simple and cheap design.  Only one person to use and materials costing less than $20!!  Here's the list of materials I used for my prototype:

For the installer:

1 - 120mm long X 57mm ID X 60mm OD PVC pipe

1 - 60mm OD pipe cap

1 - about 300mm long surgical rubber

3 - rubber bands

1 - beer bottle cozy

1 - needle and thread

For the cone and securing base:

1 - mini plastic traffic cone

1 - wooden cone

1 - 8mm bolt

2 - 8mm nuts

1 - 8mm washer

1 - 8mm lock washer

1 - piece of wooden plank

1 - epoxy

How to make the installer:

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  Cut your PVC pipe to length.  The length doesn't need to be exact.  But you don't want it too long or else the legs of the installer will be flimsy or too short that it wont clear the base cone.  I settled for 120mm for my length.  An important key in selecting the correct PVC pipe is the inner diameter (ID).  It should be in a range about 57mm to 60mm ID which is about the size of the inner diameter of the clutch's spring groove.  Also, you don't want to use a PVC pipe that's too thick because you need it to flex.
  
  
  
  
   

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  I had some time at work so I made a template on CADD to cut the grooves on my PVC pipe.  You can download it here.

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  Cut out the blackened areas.  What remains will be the legs of the installer that pushes the spring on.  I found that if you have too many legs, the installer legs will be too flimsy to be effective.  Put as much or as little legs you can fit on the circumference length of the pipe.  When the legs are compress together, the new pipe diameter is about 40mm (See smallest circle on template picture above).

• Tape the template around the pipe and trace the legs onto the pipe.

• Get your Dremel cutting wheel and start cutting out the legs.  Use a sanding bit to smooth out any rough edges and round out the radii.

• Take your beer bottle cozy and cut out the zipper.  If you can find one without a zipper, more power to you.  Sew up where you cut out the zipper.  Also, fold down about 3mm off the top and sew it down.  You want all your stitching on the label side of the cozy because you want the side that goes against the pipe as smooth as possible.  Don't forget to cut the bottom out.

• Cut three pieces of surgical rubber.  Size two of the pieces so it compresses onto the 40mm diameter tip of the pipe and the third piece so that in compress the 60mm diameter portion of the pipe.  Use rubber bands to tie the surgical rubber together.  I found that this is the best way to tie surgical rubber together.  

• Install the modified cozy onto the pipe.  The tip of the cozy should not be installed to the tip of the pipe.  Leave some room for the spring to ride up.  Next, install the surgical rubber band pieces.  (Note:  I use a cozy because its elastic and I needed something to place around the pipe so that the surgical rubber bands doesn't slip off the pipe.)

• Make final adjustments to the positions of the surgical rubber bands and cozy.  Fold down the excess bottom of the cozy over the top surgical rubber band.  Put the pipe cap on the top of the pipe. 

• The Puch ZA50 clutch spring installation tool:

 

How to build the cone & securing base:

• Get the mini plastic traffic cone.  I bought this one for a 100 yen (or 99 cents) store here in Japan.  Cut it down until it fits onto the inner diameter of the spring groove.  The base should be about 57mm to 60mm in diameter.  I cut this cone down to size by a lot.

 

• Get the wooden cone and trim it down to fit into the plastic cone.  Trim it down enough so that its about 2mm deep inside the cone so that it clears the spacers found on top of the clutch (second gear).  The base of this cone is about 55mm in diameter.  Drill a hole to fit the 8mm nut.  Epoxy everything together.  The purpose of this inner wooden cone is to reinforce the plastic cone from the clutch spring's compression and to hold the 8mm nut in place.

 

• I made the base out of a scrap piece of wood plank.  Drill a hole in the center to fit the 8mm screw through.  Countersink the bottom.  Add a flat washer and lock washer to the bottom.  Cut the 8mm screw as need to make the cone fit snug against the clutch.  Length of screw was about 45mm.  Hold the screw in with the 8mm nut.

• The cone & securing base set up:

How it works:

• Place the clutch onto the securing base.  Screw cone down onto the clutch.  Tighten screw to the cone so that it securely holds the clutch down.  Make sure cone is aligned on the center of clutch.

 

 

• Put the spring onto the cone.  Take the installer and align it on top of the cone with the 40mm diameter opening down.  Slowly push down.  The spring should work itself down smoothly and settle into the clutch spring groove with one good push.  If the spring is too stiff and riding up the cone, add another surgical rubber band piece around the 40mm end to add more compression.

 

 

• After the spring is in, remove the cone.  Spring installation complete!!  It couldn't be easier!!

20# Tomos blue spring on second gear clutch

30# Tomos red spring on first gear clutch

In the video, the spring installation shown is the Tomos 20# blue spring uncut on a second gear clutch and the 30# Tomos red spring uncut on a first gear clutch.  As you saw, both were successful.  No deformation of any of the springs.  Now all you ZA50 modders can find tune your clutches almost as easy as an E50 motor.

(This design is probably adaptable for Tomos clutches too!!)

So get modifying and happy tuning!!