Guys.. i think its time for me to change my piping ...
my putra is in STOCK .. and been running for 330k km ... Overhauled a year ago. I wanted to keep it STOCK as possible, but i do think there is a lot carbon deposit after such a long run.

What is the original piping size ?
and what is the recommended piping size to upgrade ??
planning to keep the muffler ori also