in all fairness that dirt is behind the inlet pipe not an easy place to clean and i don't think he is thinking of entering it in a concourse competition
i bashed out the restrictive bit in the bottom cut off the raised bit in the lid then used a montesa 348 filter which covers the airbox with about an inch overlap refitted the lid the screws just pass through the filter but i cant tell you how well it performs off work at the moment bad back
