BADASS SHARKS 2-Stroke Exhaust Muffler 22mm 50cc-150cc | Stainless Steel | Matte Black Finish | Fits 50cc-150cc Engines | 280mm Total Length | Complete Hardware Kit Included

These are a popular alternative to the stock muffler. Good luck and safe travels. https://a.co/d/0dZc7xKR

I bought this one but you will need a high temp rubber hose as well to connect it to the exhaust. https://a.co/d/006dYnBd

I run the length silencer on all of my builds with mz65 expansion chambers. It is quieter than the stock muffler and does not change engine performance. You can also cut and use the stock muffler as a silencer. Installing leaner/smaller main jet to stop four-stroking at wide open throttle dramatically improves performance with expansion chamber. That silencer is a little cheaper on eBay. Good luck https://www.amazon.com/Universal-Motorcycle-Exhaust-Muffler-Motorcross/dp/B0DFWXQ317/ref=mp_s_a_1_3?crid=YZ0UKRNRSG6T&dib=eyJ2IjoiMSJ9.uQxR37hrqcQeiUqsLMhmdgCxym-NLOOutw3YS6ndqJIAaJ8nJ9NNR8yBAFpekzLJIoovSFG0d0VOQsHIGiYosLjWGg-yNMg43NbdDzQ8YLnFf3oVDpfA4JMJ0GZZKRrmNPgY7YyNoVLUuti_BERQd06F5JdKC4nzGWO9otM1j0c4-u0594xWWhv9wlpLmLjocQaJSFBuVolcbc783qWbsQ.Iofp0q5IuLh0Qy4bk_eWHvqZ2-_-OFY2QVFP1l5NfQM&dib_tag=se&keywords=motorized+bike+silencer&qid=1766860330&sprefix=motorized+bike+sil%2Caps%2C179&sr=8-3