In an earlier edition of Q&A Lee was asking how to restore the yellowing plastic of the petrol tank on his TY250. I had a similar issue with the expansion tank on my CX500 restoration. I ‘borrowed’ some bleach from under the kitchen sink, made up a fairly strong solution with water and immersed the tank in it for a few days. The result was a much brighter looking (and better smelling) tank. Remains to be seen how long it takes for it to go yellow again though!
I have just seen the letter from someone asking how to sort a yellowing plastic tank on a TY250. I don’t know if this will work 100%, but I don’t see why it wouldn’t and it’s worth a try: https://www.youtube.com/watch?v=VU7vXMezW_I