I just intalled a YZ450 Pipe I scored from ebay on my WR450 and it bolted right up. You just need a longer rear bolt since the mount bracket on the yz pipe is thicker than the wr's stock pipe. You need to carve a little on the rear fender to make a larger area for the rear mount bracket to fit through. Other than that it is a perfect fit. I also picked up a Pro Moto Billet
end cap with the spark arrester and the quiet insert and it breathes way better than the Canadian stocker and is a little louder. My guess is it's probably at 95-96db. If you remove the quiet insert it must be 101db, maybe a little more than the stocker. I saved about $80 from bying the FMF
Q and it is tunable for Moto. I noticed an increase in throttle response and it has a better mid hit and more top. I may need to put in a larger main jet and I moved the clip down one spot on the needle. It looks pretty trick too.
Canadian WR450 W/Street Plate, Baja Designs
dual Sport Kit, YZ 450 Pipe/Pro Moto Billet end cap, e-line skid plate
, frame guards, fork guards, Pro-tapers, Devol Rad Guards
, Digital Speedo, Cycra
MX Hand guards, Half Vent Front Nuber plate & YZ rear fender for moto.
Stock is 48 pilot, 160 Main for now/may need to increase it, Canadian needle jet is 3 richer than US and the clip is in the 5th position