Yes possible, while trying to do research on it I came across one of kartfabs videos where he used something like that, but it didn’t seem to help.
Maybe he could chime in?
1) stock muffler will be good haha
2) open pipe is loud yes
3) ebay muffler for pit bike is just like running and open header anyway. I honestly believe they are made to make a 125cc pit bike sound louder than the stock muffler
4) RLV mufflers do work ok but they dont work really well like you would expect a muffler to work. They do actually quiet the noise down a bit. The cross section is perforated steel circles (a big circle with smaller circles punched into it). The open RLV muffler is like a square mesh that doesnt do much muffling at all.
5) if you want your mini bike to be quiet, you need to find a 4 stroke muffler off a stock 4 stroke dirt bike. People are always wanting to make their stuff loud, or "deep sounding" and they pull the stock muffler off and sell it on ebay. If you get a honda grom muffler, it has a 1" ID inlet on it that will fit most 1" headers that are common for predator 212 engines. I put one on my nephews mini bike and he was ****ed because it actually worked (he liked ear bleeding pops). The thing is actually really really good at being a muffler. Again, honda grom muffler. search for a used one on ebay. With that said though, the trade off for a muffler that works is size and weight. Its going to be HUGE and heavy.
Good luck.
here are some videos on the bike im talking about. This is after he trashed the seal of the muffler wrecking his bike. Even with the bad seal it still is quiet.
https://youtu.be/CPjUuhnYHxU?t=295
And then i did a video with carsand cameras when it was running quiet. Should have added a second support but you can see how big it is.
https://www.youtube.com/watch?v=46TS3O5UtSM
