Magic solutions such as the K&N filter do not appear effective, which does not greatly surprise me - the stock K bike filter is close in filtering area to the filter used on the 3.5 l BMW car engines. I do not believe the stock filter is the restricting item in the K bike air-flow tract. In addition, since there is no obvious performance improvement running the bike with NO filter (and the airbox wide open) - the snorkel leading to the airbox does not appear to be a restriction, and indeed under normal conditions (with some ram-air input to the snorkel) it may improve the overall output of the engine.
Contacting me:I will be glad to discuss the results above to anyone who is truly interested in pursuing them. If you feel I've stepped on your toes by providing facts, please do not contact me (it would be a waste of your time and mine, more or less like wrestling a pig in mud!) I can be reached at: email@example.com
Don Eilenberger, NJ Shore BMW Riders
Thanks MUCH to Frank Armadruto of Sun Cycle in Manasquan NJ for his help and patience in doing these runs. If you need an excellent mechanic in the NJ area I would be hard pressed to recommend anyone higher than I would recommend Frank!
Also - thanks to Brian Curry and Anton Largiader for the loan of various L-Jetronic components which made the presentation much more interesting, and to Terry Evans for the loan of the K&N air filter!