Sub Air Filter Info

Sub Air Filters are they important?

They filter the contaminated outside world air entering the carb vacuum chambers,
which need to be fastidiously clean to do their job properly. Without them airborne
dirt can make its way into the vacuum circuit then into rest of the carb and the
intake tract via the slide lift holes.
Understand that carbs need a standard atmospheric pressure of clean air to operate
correctly, instead of the huge and wildly varying pressures (big twins are like the)
and constantly reversing Helmholtz wave within the air box. That wave propagates
from throttle open induction (+), exhaust designed back pressure (-) and also from
happens when you close the throttle (-), this due to cam timing and cam overlap (the
time that the induction/exhaust tract is open end to end, from the air box snorkel to
the tip of the exhaust cans).
Another reason that they are important is that the filtered air circuit (which utilizes
filter foam of a specific designed porosity), ever so slightly damps (slows) the
backside of the slide lift circuit, this by-product of filtering bothers nothing, so long
as the value of the damping from carb to carb is the same. So having one in and one
out would slightly alter the rate of lift (opening) for either slide.
In carb tuning land, a precise and perfectly simultaneous opening of the slides is
paramount to not having a stumble, flat spot etc. It is important to try and achieve
this mechanically first before fing with the vacuum through balancing of the throttle
plate angle. So yes the filters are important to the bike's as are clean, non-porous,
non-sticky slide diaphragms, and fastidiously slide lift bobbins and carb body lift
bores... Happy carb tuning everyone!

Now if they aren't in there most likely the remnants of them are sitting on top of
your carb slide diaphragms. This will need a clean out...

The foamies are a service item replace them every them every five years or 20,000
miles. They do last longer if you give them a wash with say simple green or down
dishwashing soap when you service the main air filter on the bike.

They get fitted dry, no oil needed
Partzilla, FILTER, SUB-AIR CLEANER
Honda p/n: 17254-MBB-OOO

Ron Ayers Honda, FILTER, SUB-AIR CLEANER
Honda p/n: 17254-MBB-OOO

Bike Bandit, FILTER, SUB-AIR CLEANER
Honda p/n: 17254-MBB-OOO