What a job I had changing my air filter yesterday. I thought it would take about 5 mins but the cylindrical airbox on the mk1 172 is an absolute pig to take off. Everything is so squashed in the engine bay that I had to take out the battery, loosen off some brackets and eventually force of the air pipe from the top of the engine so I could open thye top of the airbox. Must be one of the reasons it was changed on the mk2.