Stock header modification

[Dennis]

A stock header (primaries, all the way back to the mid-pipes) work just fine on a stock engine. Don't mess with them. What you did looks fine.

 

[PhillipHarvey]

Hello guys hope you're good, there are some udpates after i modded my stock header to 4-2-1.
Before, i just modded the diameter of the end pipe (60mm). Now, i modded the secondary tubes to 50 mm but i did not mod the primary tubes they are Still stock size (38mm) should i mod them too ?

I guess you should do so a bit for adjusting the size accurately.

 

[Busa4Fun]

I tooked the fairings off yesterday and i had à better view of the modded stock header, here is it if someone is intérested how it looks like