2001 XR400 I was changing my spark plug, and it only took a few turns to get the old plug out. The new plug goes in a couple of threads by hand, and then a couple more with moderate force (< 13 ft-lbs). Is this normal, or should it go in all the way until the metal seat of the plug makes contact and compresses (like a car spark plug would)? I took the tank off, laid the bike on its side, and blew all the dirt out before removing the old plug, so I don't believe there is any dirt in the threads. Edit: The spark plug threads don't seem to be deforming, and there is no Aluminum on the plug when I pulled it back out, so I don't think it is cross-threading either.