I would check the Clutch Slave!I have an 88' 1500 that started to leak about 6 months ago. It's like colored sticky water. Seems too loose to be oil, and it has no smell, so I doubt it's fuel. It leaks directly under the engine toward the rear. My excellent local Fort Worth, TX mechanic has had the bike almost completely torn down and could find nothing.
Any ideas? Here's a pic and link to a video.