I was just reading a discussion here about which mufflers/silencers were quieter or louder, 4-into-1 or 4-into-2, etc.
The number of mufflers attached to your headers doesn't dictate whether they are loud or not; it's the baffles inside that matter.
- Even stock CB750K 4-into-4 exhaust systems differ in sound between 1969 to 1978. HM300 were louder than HM340 and HM341 and they all sound different. The 1975 CB750F (Supersport) had a completely different (and quieter) muffler than those used in 1977-78 -- even though both were 4-into-1. (The F1 pipe went all the way to the back of the motorcycle! It looked like a cannon.)
- Whether you have a diffuser on the back of your stock pipes changes things too. My CB750K6 has stock, 47 year old, HM341 4-into-4s but are missing the 4 diffusers, and are pretty damn loud. You can definitely here me coming. Again, the stock 4-into-1 from the F1 was much quieter. It was truly a "Muffler".
- OEM vs. Cheap aftermarket vs. Expensive aftermarket: A stock, 1975 CB750F 4-into-1 exhaust is vastly quieter than aftermarket 4-into-2 pipes. My old 4-to-2s sounded like a pair of trombones! I even wondered if there was even anything in there. They weren't just loud, they blew out all of my bike's power out the ass end until I changed them to the F1 muffler. The old performance 4-into-1 Kerker was louder than stock F1, but quieter than my 4-to-2.
- New vs. old and crusty. You can have a 50 year old set of pipes that look good on the outside but may have a lot of holes inside due to 5 decades of internal rusting. In such a case, NO$ (New, old stock) pipes of the same model would likely be quieter.
This is just based on personal experience, so probably not "the definitive word", so other geezers feel free to "Pipe up".
The number of mufflers attached to your headers doesn't dictate whether they are loud or not; it's the baffles inside that matter.
- Even stock CB750K 4-into-4 exhaust systems differ in sound between 1969 to 1978. HM300 were louder than HM340 and HM341 and they all sound different. The 1975 CB750F (Supersport) had a completely different (and quieter) muffler than those used in 1977-78 -- even though both were 4-into-1. (The F1 pipe went all the way to the back of the motorcycle! It looked like a cannon.)
- Whether you have a diffuser on the back of your stock pipes changes things too. My CB750K6 has stock, 47 year old, HM341 4-into-4s but are missing the 4 diffusers, and are pretty damn loud. You can definitely here me coming. Again, the stock 4-into-1 from the F1 was much quieter. It was truly a "Muffler".
- OEM vs. Cheap aftermarket vs. Expensive aftermarket: A stock, 1975 CB750F 4-into-1 exhaust is vastly quieter than aftermarket 4-into-2 pipes. My old 4-to-2s sounded like a pair of trombones! I even wondered if there was even anything in there. They weren't just loud, they blew out all of my bike's power out the ass end until I changed them to the F1 muffler. The old performance 4-into-1 Kerker was louder than stock F1, but quieter than my 4-to-2.
- New vs. old and crusty. You can have a 50 year old set of pipes that look good on the outside but may have a lot of holes inside due to 5 decades of internal rusting. In such a case, NO$ (New, old stock) pipes of the same model would likely be quieter.
This is just based on personal experience, so probably not "the definitive word", so other geezers feel free to "Pipe up".
