Originally Posted by Massi_torino
Good afternoon,
So, the P.N. on the silencer is AER 4500. The peculiarity is that it's welded to the pipe that extends all the way to the rear, as well as the front, so the 1105 suggested to Dave can't simply be swapped out without extensive modifications or even replacing the pipes. Strange but true. This type of silencer was installed at the factory.
Suggestions?

That's interesting. The factory side exit Sports exhaust for 3.7 Roadster also have the tail diffusers welded to the silencer back plate. In this case the pipe is so short as to be irrelevant.

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Note the Plus 4 used the same silencer MEX1105 as 3.7 Roadster. This means the separate rear pipe and tail diffuser will fit your Plus 4 as well, confirmed by part number. I have these latter parts (MEX1184) surplus plus hanger, after fitting above sports pipes. PM if interested as all you will then need to convert to standard quieter factory system is an MEX1105 silencer - unfortunately I sold both of mine.

Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone