I used one straight and one curved brass pipe fittings. The end of the expansion pipe was smaller than the end of the silencer so the straight fitting had to be a reducer with the small end going over the end of the expansion pipe. a slightly curved fitting was put in the larger end of the reducer to change the direction away from the bike. The silencer fit over the top of the curved fitting. Then I used heat exhaust thermal wrap and wrapped it around the connection and secured it with hose clamps. The silencer is held to the frame by a piece of iron and a large clamp that fit around the frame. The piece of iron had to be bent slightly to line up properly. A hole was drilled in the end of the piece of iron to hold the silencer on with a screw and lock nut.
@pjamin10 Oh yeah, it purrs like a kitten, can hardly tell it's a 2 stroke with that FMF powercore2 silencer. I really had planned to get the FMF powercore2 "shorty" which is shorter than the one I got but I got an unbelievable deal on the longer silencer I had to go for it.