It'll cost you around $10 for a tap that will allow you to use Keihin slow jets in a Shin Wei. I don't remember the tap size off offhand though. The difference between the Shin Wei and the Keihin is the Shin Wei slow jet is threaded at the tip.
Here are the jets that will work once it has been threaded:
https://www.aliexpress.com/item/20-P...812805848.html