WHAT IS IT? MSR’s Funnel Web air filter is made in
Australia and is known for its pyramid-like bumps, dome
shape and single layer of single-density polyurethane
foam. The funny shape has a purpose, as it increases
the outer surface area to almost double that of a
conventional air filter.
WHAT’S IT COST? $49.95.
CONTACT? www.msracing.com or
WHAT STANDS OUT? Here’s a list of things that
stand out with the MSR Funnel Web air filter.
(1) Theory. Motocross bikes have used all manner of
air filters over the last 60 years. There have been paper
filters, fuzzy filters, multi-density filters, domed filters,
pleated gauze filters, dual-layer filters, throw-away filters
and green weenie filters. Regardless of its shape or construction, the goal of every air filter is to let air in while
keeping dirt out. Air filters are one area of motocross
development where there is still unlimited potential for
creative entrepreneurs, as the FunnelWeb filter shows.
( 2) Design. The one-piece, pyramid design provides
a larger surface area than most filters. Increased surface
area allows less dirt to penetrate the foam. It is easy to
get confused about the relationship between filter size
and airflow. While the Funnel Web has twice as much
surface area on its outer diameter, thanks to the 203
pyramids on the 2016 KTM filter, it is not any larger
where the air filter cage mates to the intake tract. No
matter how large the outer surface area, the air still must
go through the same size intake tract. But all is not lost.
The greater surface area of the Funnel Web means that
the chance of airflow being impeded as the filter gets
clogged with dirt is reduced. There are more places
for the air to get in, and this translates into longer
( 3) Construction. Why does FunnelWeb use a
single-density, single-layer foam instead of the dual
layers of other air filters? (a) The single-layer foam holds
its shape better. (b) The single-layer foam does not get
dirt stuck between layers, because there are no layers.
(c) FunnelWeb believes that a thicker single layer of
foam provides better dirt filtration than a filter that has
one dense layer and one porous layer. Additionally,
MSR’s FunnelWeb filter is not flame-bonded together; it
is sealed with a petroleum-resistant glue instead.
( 4) Seal. To get the best seal possible between the air
filter and the airbox lip, FunnelWeb injection-molds a urethane seal for a tighter fit to support a layer of dense foam
seal between the cage and the airbox. MXA still
puts grease on the seal for extra security.
( 5) Performance. In MXA’s tests, the FunnelWeb air
filter did its job well. We tested it in extreme dust and
sand at the back of the pack. There were no signs of dirt
bypassing the oiled foam. The larger surface area was a
plus on the maintenance side of things, but if there was
a performance gain over the stock air filter, our test riders
didn’t notice it.
WHAT’S THE SQUAWK? The foam pyramids can be
damaged by rough handling during cleaning and oiling.
Since all filters are made of foam, designers
can only change density, layers and shape.
FunnelWeb’s choices result in a filter that is
durable and long-lasting.
MSR FUNNELWEB AIR FILTER
MXA TEAM TESTED