Insizwa
CB750 New member
Hi Guys, I have a 1976 750 K5 that I am trying to register (in Portugal). The exhaust noise test results came in at 98bB at 4000 rpm whereas the original registration papers have the acceptable level at 78 dB. Is there a way I can temporarily or permanently reduce this for a follow up test? The bike has stock pipes with small diffusers at the end. Thanks in advance for your help. Grant