Notice the power 8.1KW, how choked up are these to get them to meet ADR's (Australian design rules).







 
 
It is essentially the same as the std late model CR500 muffler. Made by HM, but not 'fancy' in any way. 1st section after external stinger in 32mm perf, then a chamber (as the std CR500 had), then just the 20mm ID perf. section. Perf , of course, with packing around it. If you have the std 500 muffler , you could just put a smaller core in the last section. Mind you, a well packed, std. late model CR500 muffler, is pretty good with noise. Other than when you pin it. Still, much quieter than the typical 4t MXer. 500s though, are producing relatively low frequency noises, for a 2t, that can carry much further, like 4ts do.B440 wrote:Hey bearorso, can you post some pictures of the long quiet muffler, both the external and internals? I don't think we have anything like that in the USA, but I could build it if I had a few pics.
 . One, is huge , oval bodied, with thick walls,  2 Ex 4t bodies welded together that I've used for it's heavy duty features - I regulary 'jump ship', and let my bike tumble off a precipice. I  have the first 305mm of the perf. core in 32mm, then the next 305mm in 28.6mm core.  I also use, for racing, riding where I want both a legal sound level, and much lighter weight, a 75mm O.D., thin walled, round muffler, with all 600mm of perf. core being 32mm. These, I make myself. Both, are very quiet, but work very , very well. As their overall length, including the external stinger, is equal to the overall external stinger and perf. core length of the std muffler. I Never use the shortened muffler, nor an FMF Power Core 2 I also have - I find absolutely no benefit in using them, and far too much bloody noise, for both my riding areas, and for me myself. I HATE, loud bikes, of any type.
. One, is huge , oval bodied, with thick walls,  2 Ex 4t bodies welded together that I've used for it's heavy duty features - I regulary 'jump ship', and let my bike tumble off a precipice. I  have the first 305mm of the perf. core in 32mm, then the next 305mm in 28.6mm core.  I also use, for racing, riding where I want both a legal sound level, and much lighter weight, a 75mm O.D., thin walled, round muffler, with all 600mm of perf. core being 32mm. These, I make myself. Both, are very quiet, but work very , very well. As their overall length, including the external stinger, is equal to the overall external stinger and perf. core length of the std muffler. I Never use the shortened muffler, nor an FMF Power Core 2 I also have - I find absolutely no benefit in using them, and far too much bloody noise, for both my riding areas, and for me myself. I HATE, loud bikes, of any type. I'll be wanting one of those, so make at least two please, seriously.bearorso wrote:I'll be making a muffler, that does not need packing, later in the year - purely mechanical baffling. I've got together with a mate who's a thermodynamics engineer, and done some research, and we are confident that we can do a muffler, that still provides the stinger effect, that will not harm the power , whilst being a near zero maintenance item. All stainless internals, and lite weight. Plus, able to be much shorter than quiet, absorption / packing mufflers.