I have heard very good things about Pig Spit (
Pig Spit - Products to Clean and Protect your Motorcycle )
Here's a pic of a 3 year old engine bay with some:
He cleaned the engine in this order:
1. Spray S100 liberally on a cool motor, let sit for about 5 minutes
2. Hose it off and grab your leaf blower, dry as good as possible.
3. Spray Pig Spit all over everything, close hood and walk away.
4. Return in 30 mins to a luster that will last several months!