expansion chamber help

[pedropete91]

hey i have an a80 36t speed carby i put my mates expansion champer on my bike and didnt really make a difference (sound wise) sounded allmost like my stock exhaust when we put it back on his it sounded like a 2 stroke any know why this is?

 

[Fabian]

I would be happy that the expansion chamber sounded as quiet as the stock exhaust - please tell me the secret for making it so quiet...