volksjagger, can you do us in Europe a favour?:
I notice that your exhaust pipe does not have a secondary air inlet port, so I think that your silencer has no oxidation catalyst either. Both these items are needed here in the EU to comply with some fatuous regulations about emissions.
If you have a look down the muffler, on the pipe end, can you see a honeycomb-like device plugging the intake? this is the catalyser.
It looks something like one of these: