Cheers mateThat would be the best way to go. It looks like you're in England and not sure what your access to used parts may be. You could identify the head pipe and exhaust (probably 2 different brands and maybe for different year model bikes) and see if you could find the matching opposite part. There should be some info stamped into them that would help you identify. That head pipe is pretty much toast. If you have some decent tools and metal skills, you could possibly hammer out those dents but it would take a some time and effort. Definitely would be easier to take BWM's advice.
Would I just type in “wr450f complete exhaust system” ?Complete system is in order . Check EBAY For stock muffler complete . If its good enough for Yamaha , it's good for me .. I doubt you need more power , torque .....
My bike is jyacj04w000011044 do you know what year this is pleaseYou should type in your year model as well since there are different engines used over the years which use different pipe size/configurations.
Check the other thread you started asking this. I believe it's a 2010.My bike is jyacj04w000011044 do you know what year this is please