I have a CRF450 end can on my XR400 and It was a bit noisy so I stripped it down to repack. I purchased some of the newer type packing with the thread that melts and lets the packing fill the can. When I opened up the can there is a roll of wire wool encompassed with some super fine mesh. It obviously a production Honda set up. The original packing was almost non existent and just about 3/4" thick around the outside of the can. The new packing said to use directly on the perforated tube so I left out the Honda wire mesh wrap. I fitted the new packing fairly snug to the sides but not too tight that it was hard to get back together. After reassembling using high temp silicone I have run it up and its possibly louder than before! Should I redo using the wire mesh set up and with a traditional type of packing? Should I use wire wool instead wrapped tightly around the tube then pack? If using the older style packing should I ram it in or leave it loose? Its a straight though pipe. If I want to quieten it I seen some short perforated tubes welded to a shorted inner end tube reducing the bore. Is this for spark arrestment only or will it reduce the noise / power? I'm a fabricator so can make most things if required.