If I go to my local motor factor and buy an oil filter of the right size, will it fit my bike engine? Are the thread size and pitch standard on modern engines? It is a piaggio QUASAR 250 scooter engine BTW. I suddenly have some free time tomorrow and don't want to wait for one by post.

the thread may be the same ( dont know ) but what about mating face . volume. pressure restriction etc

you need to be careful with the bypass pressure rating, if its too low or high you could lunch your engine

I didn't know that. I just thought it was a paper element in a tin. It just goes to show it's always worth asking.

but there is no standard thread either.....

halfords do motorcycle oil filters.

Halfords are pretty poor at knowing which one you should get. In the end I went to a scooter shop about half an hour away. They just put their hand on one without looking. Apparently all Italian scooters under 300cc use the same filter.