Headcups

An update of the headcups was necessary.
Made them really quick about fifteen years ago when I built the Zündapp.
Borrowed a friend's lathe at his work one night.
Back then I sucked even more than today when it came to using a lathe.
But function wise they turned out really good and have served it's purpose well over the years.
This winter with the whole rebuild they needed some TLC as well.

The old version

The updated and smooth version

Welded back with a little wider stop so the triple tree don't hit the tank anymore. 

I also removed the steering lock because it doesn't fill any purpose anymore with the KS125 forks.

Getting jiggy with it

Delay in da shop.
Needed a jig for the Zündapp build.
Some brainstorming and once again my trusty +20 year old Black & Decker workbench came useful. A piece of metal in bottom of the frame fixated in the bench wise and two straps was the solution.
Now It's in a better height and the workbench and wise is free to use for fabrication again.
Moving around is also possible now unlike when I had it in the workbench wise.

PartZ

First batch with Zündapp goodies except for the already arrived spokes.
This time just quite boring replacement parts.
So to spice up things I took the expensive choice and went for the stainless steel alternative.
Axles and chain tensioners are in this premium choice.
The rest are hollow axle, swing bushings and rubber for the elastic sprocket mount.
I also went for the red NGK spark plug cap/wire.
Also planning to upgrade the ignition/charging system from 6 to 12V and besides that a red "Racing Cable" maybe makes things a little more spicy?

Fan...

Not used at all of this. 

But actually really nice to meet a fan.

Me and the fan 

Smooth Rollin'

Both hubs was in desperate need of new bearings.
Rear because they were just old and rusty.
The OEM Zündapp/Marzocchi front axle have larger diameter than the donor bike so the old bearings had to go there as well.

For the rear I bought SKF local of the shelf.
But in the front I had to go abroad because of the odd bearing size needed.
I found a OEM Suzuki bearing from Koyo in the UK with the new specs needed for the conversion.

To remove the old bearings I just welded a nut to the old bearing and used a slide hammer and out they came.

In the rear it was just a replacement job.
But in the front I also had to machine the center spacer between the bearings from 15mm to 17mm.
And after that it was a straight forward job even in the front.

Next up was the spacer.

I machined the old OEM Zündapp brass spacer to the new measurements and suddenly I had a Yamaha brake hub in a Zündapp/Marzocchi fork.

Next up, fork deconstruction to give the triple tree and legs some massage and shine....

Beefing up the Zündapp frame

Another frame mod that I actually did four years ago was to beef up the swingarm pivot point.
The change is to the new type from the newer Zündapp model.
The swingarm axle diameter is increased from 10 to 14mm.
I have a friend who did this way back so I was keen to try it myself on my ride.
Have no idea how he did but this is how I did it.

This was now possible because I just bought the TIG welder at the time.
So a newer Zündapp "529" frame was bought and butchered up and my older Zündapp "517" frame was cut to accept that piece.
But before any cutting on the old frame could be done a fixture was fabricated to maintain everything straight and on the same position.
When the fixture was made I just had to cut it and increase the swingarm mounting hole from 10 to 14mm and slide the beefy part into place and secure it to the fixture before the TIG was fired up.

Fixture done and the "517" frame ready for cut.

Old "517" frame cut and trimmed to accept the new "529" frame part.

The new "529" swingarm mount testfitted.

The new "529" piece part of the old "517 frame.

Here is the lower M10 fixation point enlarged with the beefier M14 rod.

Just some nice welds and the job is done

Straightening the Zündapp frame

When i´m now rebuilding my old friend the frame needed some love and affection.
First up, straighten it.
The frame had been involved in some serious wall hitting or something similar in the past and this had to be reversed.
The weapon of choice was brute force and fire, an ancient combo that have been successful since day one.

The before shot

The torch was lit and with some heat on strategic spots in combination with me pulling it in the right directions the work was done.
Straight as a ruler? Nah. But definitely good enough.

Mayhem to be made