My old bike was white, always looked good and clean!
My Fazer is black, dirty bastard......cannot keep it clean at all, even after a wash, you still get water stains and any dirt looks, basically. dirty!!
As much as i love my bike, i wouldn't buy black again in all honesty, maybe grey or silver!
When your black engine is cold...spray
tyre foam on it. Gets rid of water stains, dirty dusty look and makes the area you spray it on glossy and new even after a good few rides including the engine. Spray on any "dusty looking" bits but be careful in around the braking area. Works a treat on my all black Bandit 1200 and on the black engine of my Fazer.
I use Turtle Corkpit Shine on the plastics, cockpit, light & indicator switches, mudguard ect that put a lovely shinea with a nice smell as well!! I use and any good wax polish on the paintwork. Those 3 products will bring your bike back to life. If I had black downpipes, I'd give them a re-spray carefully on the bike with heated resistant paint every so often. The Barbeque Oven paint found in DIYs does a good job.