Never lube a dirty chain on the bike. Remove it and put it a plastic jar with Simple Green or mineral spirits and shake it for a few minutes. Rinse, dry and lube.
I use an ultra sonic parts cleaner and my road chain was replaced at over 17000 miles. The tourer has 20100 miles on the chain. I think the fender with mud flap keeps the crud off.
When I have the chain off I wipe the crud off of the rest of the drive train. I lube the chain with 1part chainsaw bar oil to 4 parts unscented mineral spirits. I clean and lube every 800 miles.