My bike was always loud and today I've decided to meassure Db with a phone. On idle has it shown 80 Db on 20-25% trottle 105db :/. According to spec should it be 79Db for 3500RPM. I was looking for some info what to do or what can be the cause in google. What I have learned - this kind of muffler shouldn't have replacable stuffing. Is it correct? What can be the reason for the noise other than used muffler? Should I buy a new or something else can be a reason or solution. The noise is really tiring and is causing issues with MOT.
I have used guidelines for meassurment. I'm not sure how phone is accurate but according to youtube is quite accurate :).
Since I've bought my bike I haven't done any modification. Previous owner shortened the exhaust pipe. My bike was produced in 2001.
You are correct that the standard muffler does not have any replaceable packing material. If the previous owner shortened the pipe, there is a high possibility he removed much of the metal baffle inside as well, trying to get more free-flow.
Most of the aftermarket mufflers are louder than the original Yamaha one.
My TTR had the internal restrictor removed during the Pre delivery, I have a aftermarket Staintune muffler & it's rated at 94db @ 3500rpm so it meets the Australian standards...it seems loud @ 94db so perhaps the phone is not reading it right
