This model is ugly and has some sharp edges and it works for me.
The aim was to have some sort of thing which works. ;)
You can print it flat. I was able to use it successfully already 3 times to pre-load and fasten the spring alone with the engine already mounted.
I printed with:
Enjoy.
Kickstarterwelle wechseln - S51/ SR50/ Kr51-2 Tutorial
A replacemenet for this tool:
The author marked this model as their own original creation.