[AZmidget91]

K&N RU-1130 fits perfect.

 

[AZmidget91]

maybe this will work as a 12mm bung
for that adapter you posted


Oil Pan Drain Plug Weld in Kit Steel 12mm Steel Bung Steel Plug Washer | eBay


plus it has a plug too







I ordered that adapter and this plug shown above


so that should get me what I want for this bikes exhaust an easy way to test when doing any changes

this way I can look into stock air box modding and see what happens with the fueling

Why not drill and tap the current bung?