Air Filters
For the carburetors to function correctly and to protect the engine two air filters were designed. They consisted of a two sheets of aluminium rolled into tubes with a thin layer of foam clamped to one end. The other end fitted over the air inlet of the carb. Different thicknesses of foam were tried to gain the correct resistive pressure and it was found that half the thickness of the normal foam was needed. These filters were a quick simple and very efficient way of filtering the air for the purposes of getting the vehicle going. This solution is shown in the lefthand side picture below.
Subsequetly we found out that when we took the vehicle for it's first proper test drive the air filters setup shown above restricted the air too much leading to the fuel burining rich. We ended up using the original air filter from the motorbike with flexible pipes which now provides a much more consistent air flow to the engine. This better solution is shown in the righthand side picture above.