Looks like the end of the exhaust broke off behind the silencer? Or is that a mod to increase noise and add to the challenge?
Those are basically Harley type slip on mufflers available in about any motorcycle parts catalog. There are MANY companies just specializing in header pipes and mufflers for the V-Twin market. This includes motorcycle brands like Harley, Victory, Indian, Yamaha, Honda, etc. Most also make pipes and mufflers for the crotch rocket genre as well.
Being a Harley guy, I'm still not used to the sound, or rhythm of the exhaust pulsed on anything other than the 45 degree Harley V-Twins. Most all original V-twins were 45 degree, including I think the Matchless and J.A.P. motors used on the original Morgan Three Wheelers.
I watched the Alex Roy video of him and his even bigger friend running the roads in the mountains outside of LA in California. The M3W sounded loud, but still had the 56 degree sound.
There are now a couple companies here in the US that make mufflers with inlet rotary plates that with a flip of a switch can go from straight through with little deadening to a full flow through all the baffles and deadening material. So from quiet in town driving to full out straight through on the highways or back roads. They are not cheap though.
