The original airbox cover is close and doesn’t let the amount of air in to the engine as needed. Espesially if you are you using a trim exhaust system and a different engine mapping. To give some extra power from KTM 690 i decided to modificate the air intake and replace the original air filter with KTM power part air-filter.

1. I first cut of some of the plastic on the original air intake as picture shows below.
2. Then I replaced the original paper air filter with a KTM power part air filter.
3. The results is a much more lively bike. Second gear wheelies, while no problem before seemed, well, less effort.