Do you know the torque spec on that axle nut?
Yeah, they do. And yes, i have the manual but it tells you how to do it with the tool you'd have to buy. you don't need it tho. It's really quite simple. Push on the belt 1/2 way between the front and rear pulleys and see how much pressure it takes to move it a given amount. the ideal adjustment would be that when pushing it with 10 Lbs of pressure it moves 1/4". I just adjusted it to where it was at 1/4" with probably 1/2 to 3/4 of that and the chirping went away. I fear it being too tight so i just left it there. But if you have a good feel for things like this i think you can get it plenty close enough as i feel i did. Also theres a oblong hole in the lower guard that is hidden by the muffler. But the muffler has to come off anyways to get to the axl bolt. You can use that hole as a guage as described in that thread of OKCTriple's. Just another way to do it.
anyways, the procedure to tighten it goes like this..
1)-remove the muffler bolt that holds it near the rear and remove the heat shiel to get to the hose clamp that clamps the muffler to the cat. you can either remove the muffler or swing it a bit out of the way to get to the axl bolt.
2)-loosen the axl bolt
3)-loosen the outside nut on each side of the axl adjusters and spin it a bit out of the way.
4)-turn each side an equal amount, say a 8th turn and check the belt to see how much that tightened it. repeat doing a little at a time till the belt is where you want it.
5)-torque down the axl bolt then the outside nuts on the adjusters on each side to lock the adjuster nut in place
Remember to turn each side the same amount each time so as not to throw the alignment out. Also you can use the markers in the frame and adjusters on each side to make sure they are both in the same place, tho DO turn them the same amount each time anyways and use the markers to check and be sure it's not off on one side from the other. This is probably mostly known to you having adjusted chains in the past unless this is your first bike.