i have ad the tank off so many times i think i have mastered it. but it is fiddly. now i have new filter below and in front of rear tank support ,it is a little easier,just. but at least the filter is washable at service intervals. i aim to cut open the temporary one i used to italy and back to see if there is any crud. i ran the bike with new filter and blocked pairs last night.it sounded much smoother and a more stable idle ,will road test it next week when weather clear .