Quick spray down with simplle green, rinse, wipe with mr clean magic eraser. Sparkiling white. Takes less than 5 minutes to clean em including moving the bike for me (no lift).
__________________
'06 Softail Deluxe Blue/White - for sale
'08 Ultra Anniversary Edition
Got a ride to plan? Looking for a ride to join? http://www.theridecentral.com
You could try Westleys Bleche-Wite (Bleach White) just spray on. I have a stiff little brush to scrub it off, you may have to appy it twice, but it gets white walls as clean as possible.