Pull out the diaphragm of your monovalve like Brian said and you should be fine. these things can get kinda stubborn when old! As far as the K&N filter, the biggest reason most don't like them and claim they pass more dirt through the intake is because they require more frequent manintenance than what you read in the directions! You don't have to worry about sensors in the intake tract going waywire because of oil vapors from the filter, the 617.95 doesn't have any.

I prefer the K&N to a regular paper filter because we get severe dust storms here in the desert and a properly serviced and modified K&N will out run paper filters in life expectancy and perfomance hands down while maintaining good fuel economy! What I did to my filter housing was to plug up the small oil drain hole in the bottom and install a rubber bushing larger than the factory one in the lower end to keep the ait filter chamber somewhat level. Then I installed a foam pre-filter element around the K&N and oiled it really well. This is now an oil bath filter assembly where a small puddle of oil (marvel's mystery oil is good for this) is now desireable and all the incoming air is blowing small bubbles in the filter and the foam pad is acting as a wick.

Oddly enough, I know that some Marvel's Mystery Oil IS getting into the motor because I have to refresh the amount every few hundred miles and the last ime I had my intake off, those valves looked good! A side effect I didn't plan on is that Marvels helps keep carbon buildup from forming! My intake tract has always been pretty clean even when the filter was caked in fine desert dust!

I'm a believer in the K&N filter, but honestly, they are a bit lacking without the mods in my opinion. Someday I will take pics of my setup and post them here.