rattling from first to third

Hey. New issue just started for me this past week. From the time I go from a dead stop, and while I'm shifting up 1-3, there is a rattling noise. After I shift from 3 to 4, and 4 to 5, the rattling goes away. This is a 28 year old KZ650 mind you. I have been holding in the clutch while downshifting/coming to a stop, which I thought I heard wouldn't hurt it. Could this be a chain issue or something worse (more expensive)? I'm going to have it looked at later this week.

im having trouble duplicating the noise from my chair,can you be more specific on what part of bike its coming from? :laugh:

It sounds like it's coming from directly underneath, like where the clutch cable goes into the trans. The other thing that's happened, is that once I get into 2nd or 3rd, it feels like it "grabs" again, and causes a jerk throughout the bike. Again, that doesn't happen in 4th or 5th.