How can I make my 2005 trx 450 quieter myself. I like to make my own stuff so give me the old home way. Does the present muffler come apart? I have all the welding gear. Will extra packing do any good?

 

easiest way would be to make an adapter for the tip on the muffler, and hang a small secondary muffler off the rear grab bar, and run a short pipe to it, like the Stealth systems they have for utility quads. That way you could be back to stock in minutes, by unbolting the second muffler and adapter. Screwing around with the insides of the factory muffler may work, but may also seriously affect how your quad runs.

 

in addition to what wolv mentioned above- using a premium packing materiel and making the exhaust tip diameter smaller will help to quiet it down. I remember repacking my old honda cr250 2-stroke baffler to quiet it down.

I noticed that the can-am renegade has a larger diameter exhaust hole then my can-am outlander- both have the same engines and fuel systems- the outlander is quieter then the renegade... the rene sounds like a muscle car, you can hardly hear the outty.

 

Look at the benz silent rider for some ideas. You could probably mount a reversion type automotive muffler after the stock exhaust to get less sound without much change in back pressure.

 

A very simple way is to simply attach a turn down section of pipe on the end of your muffler.
While this technically won't make it quiter, it does deflect the noise down to the ground, thereby producing less db's to be heard by anyone around the machine.