poor shifting manual

My '99 SW1 has developed a shifting problem with a manual transmission. The oil checks fine. It sometimes works properly, but often won't go into a gear, any gear. I've found a loose bushing on the top of the transmission. I believe it's on the cable that chooses the gate, rather than the other cable that chooses the gear. This cable is the upper one, which operates a bell crank. It's this pivot which is loose. I wrapped some copper wire around the bushing, under the bell crank, to snug it up a bit. This is helping, but obviously not a good fix.
Does anyone have any suggestions? It looks like the bushing / pivot is pressed into the top of the transmission, which I don't think I'd like to dismantle.
Thank you
Drew

I believe I've fixed it.
I had to remove the battery and batt holder and air cleaner housings to see what i was doing. I removed the shift cables and removed the top of the transmission,(after cleaning the area), to get the bellcrank assembly out. The bellcrank has a pin thru it that was loose, so I peened it down solid again. Also, the bellcrank pivot pin was loose in the top of the transmission cover. I removed an aluminum cap to find that the C-clip which held the pin was broken, which I replaced. So it's back together, and tight, and it seems my problems are fixed, so far.