Electronic starter shaft for 49cc engine

I have a 49cc 2 stroke engine in the following format:

I also have a 12V electronic starter like this:

However what I am currently lacking is a bolt/shaft to connect the electronic starter with the engine and gearbox. I have found several locations where I find the apparently appropriate part to buy, however all of them list it as "out of stock" or "discontinued by manufacturer". Here is an example:

https://www.urbanscooters.com/products/electric-starter-bolt-shaft-part-260-26

Does anyone know what the proper name or maybe a number for this part is?