I have a 2nd bike in which the oil and filter were changed last year. It was then parked up and hasn't been used since, aside from occasionally turning the engine over. It's now ready to be MOT'd and ridden. Should I change the oil and filter again or is it not necessary?
Personally I would not bother. Ideally "engine turned over" means either just turned over without being run, or run up until a good hot temperature has been reached. However, even if a little moisture has got into the oil it will be driven off by a good ride. If you were to change the oil, I can't see any point in doing the filter - it doesn't hold much, and it won't have filtered anything out when the bike was standing.
oil will not degrade significantly if not used. It's already millions of years old, I doubt another year will effect it much.
