My 2008/2004 Service Honda uses a modified CR500 pipe and silencer built by FMF. The FMF P/N's for Service Honda were 04/122000 for the pipe, 03/09 122001 Power Core silencer and 3/20/07/122002 for the Turbine Core Q silencer. While Service Honda was building the the AF's FMF would not sell the pipes directly and had to be purchased through Service Honda. Now that Service Honda is no longer in business FMF may be willing to sell directly. The pipe is just a CR500 pipe with the KX500 exhaust flange head welded on. The silencers were also CR500 but with about an inch longer mid-pipe. I don't think it's really necessary to have the modified CR500 pipe and silencers from FMF to work. The KX500 exhaust pipe flange which can be welded on to the CR500 pipe would not be too difficult. The rest I'm sure could been done using standard CR500 silencers with a fabricated slip-on mid-pipe extension or some creative mounting adapters to the 2008 KX450F frame and subframe.
