Air filters
 

Decided to strip down the air tubes and replace/clean the air filters. The Haynes manual states "On 996 models ensure the rubber intake block is correctly seated in the housing".
Mine's a 2001 996S. I could find no such rubber block. Just a filter. Is this correct?

Cheers

They've either been removed or not included on UK-spec bikes.

The rubber restrictor annulus in the superbike inlet runners are designed to reduce air induction noise to meet US EPA noise limits. These are not inlet restrictors designed to limit performance like those used recently on some Japanese bikes to meet maximum speed limits. The superbike blocks merely increase the velocity of the air as it passes through the device but reflect sound waves back to the engine inlet. Said another way, the pressure drop across them is very low as opposed to a high pressure drop created by a dirty air filter.

i would think that they are talking about the rubber type gasket that fits between the air tube and air box often missing

As Shazaams post,....they have been removed mate.Its just a two piece block of rubber that goes in the air tubes.I removed mine from both my 996 and 998.Little or no performance gain,just a bit more airbox roar.