Part of the popping is a result of the excess air being dumped into the exhaust to create a hotter burning mixture to reduce emissions. When you decrease the flow restriction, you will notice more popping. This was an even worse issue on the ER6N due to the airbox design with the snorkle tubes. These were removed / revamped on the Z650, but you will still have some popping which is normal. Removing or bypassing the pairing valve will also reduce it to a small degree. Even after a Rapid Bike with a custom map you will still have some popping on deaccel. It's not nearly as noticeable though. The Rapid Bike will continually remap and make adjustments as long as you turn the option on in the software and over time will get better performance. I have several videos and links that go through all of this and explains the steps I've done so far to the Z. Perhaps I should make a video and go into more detail about what to expect when modifying a bike. When you derestrict an engine, it gets louder... period. You will hear and feel things you didn't previously.
Tremonte, please do if you get the time.
I think more people than I would appreciate it.
...and a lot of ppl including me seem to follow your advice
What happens if you change stock to Yoshimura other than looks?
Do you have to modify anything else on the bike?
Should you modify anything else? What is recommended?
Do you have to remap the bike?