Hi whitegreg56,
I was hoping someone would have already answered your question with some prior experience/solution. What I can tell you is that I'm sure that the squeaking is not "normal". I worked on a rental fleet of these for several years and, even though we didn't use the XRA extension, I'm fairly certain of that. So, that brings us to the next question:
Is it something to be concerned about? And, of course the answer is....I don't know. Actually, I could venture to say that , yes, it may be something to be concerned about but PROBABLY not OVERLY concerned. How's that for ambiguity eh? (something I'm fairly good at)
Squeaking is sound and sound is frequency and that usually means some sort of contact. It could be a worn seal lip on a shaft that, over the normal course of use, has started oscillating. Or, for a more sinister scenario, it could be contact between the pulsar, exciter or charge coil and the flywheel magnets. I have seen corrosion cause some "fuzz" (for lack of a better word) to grow up under there and create a little contact. Other possibilities are one or more of the coils has come loose or the crankshaft bearing has worn and there is a bit of "wobble". Much of this can be easily checked out with by removing the flywheel and taking a look. You might need a dial indicator to detect any undue crank end play.
If you take a piece of car heater hose or 1/2" garden hose you can make yourself a fairly decent "stethoscope" to try and narrow the location down to a specific area. I use old broom handles as listening devices too. JUST BE CAREFUL not to get any of that tangled up with the timing belt!
Good luck.
