Air Filter

OSSA Air Filter Systems 

OSSA used two different styles of air filters.  I'll define early bikes as those produced in 2011 and 2012.  Late bikes were manufactured in 2013 through 2015.

Early bikes came fitted with a filter assembly (part number 9310010211) that had to be completely detached from the throttle body for cleaning.  This is item #1 in the early parts diagram shown below.  Item #13 is the intake air temperature sensor, and its mounting is quite unusual.  There are two rubber “whiskers” (my made-up name for them) that hold the sensor in place.  You must stretch the whiskers through holes in the sensor to remove or install it.  Both early and late designs utilize these whiskers.  This is a recipe for eventual failure.

I can't recommend using the TwinAir filter for early bikes because it does not appear to incorporate any mounting system for the intake air temperature sensor.

Late (2013–2015) Filter System

The foam filter itself (part number 9350010213) is easy to replace and still available in the aftermarket.  Unfortunately, there is no simple upgrade path to this system for early bikes. 

Although the later filter system is arguably better, item #3 in the late parts diagram (air filter housing assembly) became unavailable shortly after OSSA's demise.  It is part number 9330010213.  If you find one, buy it! 

I suspect if the rubber whiskers ever break, you could cannibalize a filter assembly for the early bikes to cobble together something workable.

Filtered Airbox Top

Years ago, I bought a Jitsie filtered airbox top (part number JI712-999).  This is helpful with the early bikes as you can clean the filtered top instead of the internal airbox filter.  However, it does affect the fueling, and must be bent to fit.  The resulting fit is far from perfect.