I bought two of these for my Ryker.
Nothing against K&N...but my first car, a 1955 Mercury (late year production with 312 instead of 292) had the factory oil bath air filter. Messy to clean...changed to paper.
Had a K&N "cold air" unit on my 2003 Jeep Wrangler and installed K&N filter on my first Sportster.
However, I rather replace than clean.
Helped my youngest son-in-law when I was in AZ last month on his F150 (had K&N when he bought it)
1. Clear kitchen sink
2. Spray K&N detergent
3. Spray off gunk with faucet in shower mode
4. Spray K&N detergent
5. Spray from inside with faucet on shower mode
6. Carry outside...return to clean sink
7. Blow off most water from inside with leaf blower
8. Let dry in sun
9. Check occasionally, sling off water at bottom
10. Spray on oil (over something disposable) after fully dry (oil & water do not mix), just until filter media is red
11. Reinstall
K&N does have excellent flow characteristics and the intake tube on the Jeep stayed clean, even though off-road for miles, monthly going to our AZ ranch and also locally.
This link is for a Sportster air filter
http://www.knfilters.com/dynocharts/HD-0900.pdf