Looking to make up a quieter exhaust for a 600cc 4-stroke single. The current exhaust is LOUD. There is only one baffle inside with two holes in it. Anyone made up a bike exhaust? What are the main ways to reduce exhaust noise?
I assuming the exit hole on the muffler needs to be the same size as the current one due to getting rid of 600cc of exhaust for each firing. What about inside? Do multiple baffles reduce noise? As a rule of thumb I guess the size/area of the holes in the baffles need to be roughly the same as the area of the exit hole to allow unrestricted flow of the gases, but can be multiple holes as long as the area is the same. Sound right? Steel construction (current one aluminium). Quietness is more important than weight so is thicker steel quieter? Flyscreen inside reduces noise but isn't durable enough. TIA.
I wouldn't ride a quiet bike on the road. Ever. Car drivers are dangerous enough as it is. I always give it a 'blip' if they don't know I'm there.
Looks like there are a couple of addition options. A baffle that slips into the exhaust outlet reduces noise but probably not enough for what I'm looking for. This is just a short length of pipe with a heap of small holes in it. Can add another muffler after the existing one. Once mounting had been sorted this would be a quick way. Or a 6 ft length of flexible metal conduit in a coil attached to the outlet hole will quiet an existing muffler apparently.
Also point the outlet of the exhaust to the ground. Helps but the noise is still there.
Can't find anything on baffle numbers or configuration and how it affects noise. Quite a few references to packing them with fibrous matting but this isn't a long term solution. The quest continues!