Earlier this year, the USA IAME importers received a shipment of KA100 engines with faulty air box tubes installed.
A few were actually illegal, many are very close. (tube internal diameter)
It was not a large number, but since this was done by an outside supplier to IAME without their knowledge, it is not possible to track the exact supply.
Replacement tubes are now available at no charge thru IAME-USA ( EAST and WEST )
Please destroy all non-valid tubes
See the image below for identification purposes.