I'm installing the Yamaha jets that came with the bike. Includes a 110 air jet. Dirt Bike article says it goes in mouth of carb, where there is no jet currently. There are 2 holes there - 1 is a needle air jet - I removed the stock jet & tried putting the supplied air jet in there but won't thread in (this is the hole on the left as you are looking at the carb mouth - new air jet is bigger in diameter). apparently the right hole is for this air jet, and it threads in but does not bottom out & stop. So, is the 110 air jet necessary? What does it do? What happens if I don't use it? all help appreciated & thanks in advance.