I have a set of them that I bought during covid, at the time nothing else was available. They are the 341 type, they fit well on a late number K0 and look good but they sound awful. I had heard they have a baffle rattle and one of mine does also. If I leave the exhaust tips off the sound is acceptable, when on it sounds like one cylinder has a miss.
I did coat them inside with the Eastwood brand of in the pipe exhaust coating hoping it would glue things together. No luck.
I'll try to remember to snap a pic of the stamping, it might give a clue. I couldn't get any information on the origin of them either. The boxes look like Busso's although that doesn't really mean anything.
I recently got two sets of Busso no no.'s after a year wait but they were about the same price as one set from CMSNL.
Yamiya still has the best product, I have two sets now, David Silver sold me 2 of the 3 Yamiya pipes I've owned, and bought back one set on a bike I restored. They charged me shipping from Pennsylvania and that was cheap.
