starter clutch. if it is that noise and the kicker is returning to the full upright position, either something isn't spaced right inside the cover, or you timed the kicker gear incorrectly (although I think that would be hard to do while and still have everything work, which it sounds like it does). There's not much in the way of spacing on the inside of the cover for the starter gear. There's a thrust washer on the outside, but in my experience, it's absence on leads to the opposite problem, the kicker moving too far in towards the transmission and disengaging the starter gear (mainshaft) from the starter clutch.
but the part about the bike not moving backwards has me confused. do you mean clutch drag? maybe it's a slightly different noise? this all sounds very throwout bearing related to me. especially if you have that wafer style bearing.
®
