HI Zippy -
Yes - the round wire mesh filter is there and it looks clean - but I don't have the airbox.
Choke is working fine - the black lever is missing, but I can still reach in to push it on and it does kick out. I have had the whole carb apart and cleaned it.
Chains and brakes seem right.
Haven't got to the transmission yet, but I'll bet you are right, it likely needs dumped and changed.