I had this exact same problem on my 99 WR. You could kick it through with out even using the decompression lever. Once I got it fired up it ran fine. After that if you shut it off the compression was there again. Then a few days later, no compression again. That was over a year ago and I have never had a problem with it since. I was attribuiteing it to a exhaust valve sticking. (and I did check my compression release cable and it was not binding) Weird deal but I never found a answer. The problem just went away.