the needle doesn't look worn... I didn't look at the jet when it was apart... I will try to remember to check that when I attempt to get the head off. it can't hurt to clean that out can it?
You have also mentioned that I could check the rings through the exhaust... the intake is on the very top of the motor, and the exhaust on the very bottom... not the easiest to get at... I find it easier to pull the head, with the 4 stud bolts, than to take the battery off, the gas tank off, and then lean the bike upside down to get at the exhaust (really well; I did try once with the bike leaning over on its side, but it wasn't very fun... :)