I bought an '86 DR600 Dakar last year and was disappointed to find the head/cam thrashed and the counterbalancer chain broken. It ran so I bought it. What can you do - buyer beware. I now have it stripped and starting the rebuild. The head was difficult to find until I found out about the SP600s. I got a head out of California and I'm going to paint the frame once it warms up.
I'm looking forward to riding it this year (fingers crossed).