Where an off the shelf kit isn't available, a universal clamp on air filter can be a great alternative. Coming in a range of sizes and shapes, including the familiar cone filter, these allow you to select the exact filter required to fit the space available.
By moving away from the flat panel shape, you get a much bigger surface area. This allows you to get much more air through the filter into the engine, which can potentially allow for more power.
A range of shapes are available. Universal filters tend to come in conical or cylindrical shapes for normal purposes, but other more specialised shapes are available for carburetted applications.
Once you've identified the shape you require, most filters come in a range of lengths, diameters, and different neck-type/diameters to enable you to select one that precisely fits your pipework and the space available.
We also have universal induction kits. These are typically an enclosed air box with a big cone filter inside. By keeping the air filter enclosed, you can ensure that only air from a cold air feed makes it into it.
We also carry a range of universal breather filters, for crankcase breather systems.