Plugs coming loose on my XJ650

Hi all,
Morg here..
Yesterday I noticed when removing my plugs that they had become quite loose.
It took almost no effort to open them with my plug spanner. In fact one of them was almost only hand tight. I have always believed that when fitting the plugs that you should only hand tighten them first and then give them a nip with the plug spanner for fear of ringing off the threads..
I suppose with all the vibration they come loose but is this normal and should I just check them regularly.?
Thanks all.
Morg.

 

With the crush washer type plugs (it IS a crush washer, compare old to new & you'll see what I mean) the general advice is when fitting to tighten finger tight & then another 1/2 turn.

To be honest, I tend to only do that the first time when they're brand new, then when they've been in & I remove/refit them I just give them finger tight plus 1/8-1/4 turn depending on how it "feels"

If you don't trust your "feel" just use one of those old-school T-bar plug tools, the ones with the knuckle joint in. Hold it straight up like a screwdriver not a lever, with the T in one hand & tighten as tight as one hand lets you...