A few pics I took a while back is the best I can do...
Usual Exhaust Header Gasket from China is on the left... looks like a soda can cut up and crumpled like a slinky... I replaced it with a Honda gasket seen on the right
And a pic of the exhaust header "welding" restrictions (not counting the welding restrictions near the "catalytic converter")... grind/file it down, make it slightly bigger and actually "round" shaped, job is done... back pressure reduced a wee bit... on our bike I was able to go from a 21mm opening up to about 26 or 27mm (about 30% bigger) just by removing the excess/mountain welds on the inside of the pipe
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"Think as you like... but this self proclaimed Professor is always right" - Buckshot
"You never know what someone is hiding beneath their smile..." - NinjaTom - R.I.P.