MZ ETZ 125/150 | New primary drive | Neuer Primärantrieb

[intr]

This might be of interest to you. Due to ongoing issues with the primary drive in small MZ motorcycles, I decided to modify the original setup and adapt it to a different chain.
More details are covered in the video — for now, this is episode one. English and German dubbing are available, so I hope you’ll find the idea or some inspiration useful.
Best regards.

In short, the idea is to replace the 06C2 chain with a 06B2 chain, which is available for use in primary drives — for example from Renold, supplied as an endless chain made to order.
In this series, I will be manufacturing new sprockets from 17HNM steel (18CrNiMo7 according to ISO), covering the entire process from design to final machining.
For now, this is part one, where I explain the problem itself.
In my modified engine, the combination of MZA components and a Czech chain did not last even 1,500 km, so the decision was made that something had to be done about it.
Additional information can be found in the video description.

If you have any questions or suggestions, feel free to ask.

Das könnte für euch interessant sein. Aufgrund der Probleme mit dem Primärantrieb bei kleinen MZ-Motorrädern habe ich mich dazu entschlossen, den originalen Antrieb auf eine andere Kette umzurüsten.
Weitere Details werden im Video erläutert – vorerst ist dies die erste Folge. Eine englische und deutsche Sprachversion ist verfügbar, daher hoffe ich, dass ihr aus der Idee oder dem Ansatz etwas für euch mitnehmen könnt.
Viele Grüße.

https://youtu.be/ODvqHk6SYvE?si=EDR1JeeE0Y3K8obJ

[Ralle]

That‘s very interesting, thanks for sharing! Have you already finished the modified primary drive and mounted it on your ETZ? Are there perhaps already long-term experiences regarding durability? Very few people can manufacture gears themselves. Did you do that just for your own use, ore are you considering selling the gears yourself, or finding someone interested in the conversion who would sell them as a spare parts kit?

[intr]

That‘s very interesting, thanks for sharing! Have you already finished the modified primary drive and mounted it on your ETZ? Are there perhaps already long-term experiences regarding durability? Very few people can manufacture gears themselves. Did you do that just for your own use, ore are you considering selling the gears yourself, or finding someone interested in the conversion who would sell them as a spare parts kit?

No, this is my winter hobby project, which is a consequence of the engine modification and, in general, returning to riding my MZ after more than 10 years. At the beginning of the year I installed a new 175 engine and clutch assembly, rode about 1,500 km, and the chain started hitting the cover. The mileage is so low that it practically rules out any longer trips on this bike, and I have a few plans connected with 2026.

Manufacturing the sprockets is relatively straightforward, as it does not require specialized involute or module cutters — a CNC milling machine and an end mill smaller than the roller diameter are sufficient. I do not plan to produce anything for sale. The machine tools I have allow me to make these sprockets, but not in quantities that would significantly reduce the cost. Professionally, I do something completely different, although still within engineering, so the YouTube videos I record are simply a form of entertainment and a way of spending time with my son, who edits these creations of mine.

The main idea is therefore to share knowledge and the concept itself, hoping it may serve as inspiration or provide an idea for dealing with a similar problem. The setup has not been fully tested yet, but I do not expect any major issues. The chain itself is of very good quality, and the carburized and hardened sprockets should not fail like the cast iron MZA sprockets. The 06B2 chain has been used in motorcycles producing over 40 Nm of torque, so my roughly 20 Nm should not be a problem here 🙂

By the way, if anyone watched the video with the German audio version, please let me know whether everything is understandable. My understanding of German is fairly basic, so I’m not able to judge whether the AI may have mixed something up 😉 it seems fine

[Matze_2]

it seems fine

That's definitely okay!!

-- Hinzugefügt: 31.12.2025, 19:23 --

it seems fine

That's definitely okay!!