Air Filters

Every engine breathes through an air filter. This section covers the filter and the pipework that feeds it:

• replacement panel filters for the original airbox;
• complete intake systems;
• universal clamp-on and conical filters, and intake pipes;
• crankcase breather filters and cabin air filters;
• the cleaning kits, wraps and fittings that go with them.

The first choice is how far to go. A replacement panel filter drops into the original airbox and changes nothing else. A complete intake system replaces the airbox and ducting with a new filter housing or heat shield and pipework, made for one engine. Universal filters are chosen by neck diameter, which must match the pipe, and by length and outside size, which must fit the space.

The second choice is the filter media. Some filters use oiled cotton gauze, which is washed and re-oiled with a service kit; others use a dry synthetic media, which is washed and dried without oil. Both are reusable, so order the cleaning kit that matches your media along with the filter.

An open filter placed in the engine bay can draw hot air, so a heat shield, an enclosed box or a cold air feed is worth having. Breather filters on a catch tank or cam cover vent oily vapour, so they need cleaning more often than the main filter. A cabin filter is worth changing at the same service.