Oh dear, looks like sticky fingers have been in there and messing about with things they shouldn't!
You had better check everything out in there, have you got a parts manual and service or shop manual? Not sure if they are on this forum, need to have a look, otherwise you can download parts manual and all sorts of interesting stuff, pictures etc from yamaparts.
http://www.yamaparts.com/manuals/The european and us rd125s are very similar but be aware some bits will be different, lots of info in the states as it was a popular little bike, sites such as partzilla, boats.net etc. in the u.s. Have on line parts lists. For parts you should be spoilt for choice over there! Pick a big yam dealer or one of the specialist sites that know these old machines, e.g. H V Cycle. Climer manual is quite good for the u.s. Models of the little yams.
Part number for crank o ring is 93210-18023 or its new number 93210-180A6-00
There is one on the clutch but its much larger and fits on the outside of the basket, i.e. Between the primary driven gear and the basket, its just a shock absorber type thing not a seal, part number 132-16369-00. I assume you dont mean the rubber rings that fit between the steel plates and the friction plates? There are 5 of these I think, not strictly necessary and un obtainable, but if you have them and they are good, use them.
The thrust washer and bearing behind the inner clutch hub come as a pair, the parts manual will detail two part numbers but this is wrong. For the pair, i.e. Washer and roller bearing washer the part number is, 93341-22302-00.
