If you have not moved the engine, it should be straight.
Alright, here they are for those who have to have a picture.
First off before you put it on the table, remove the wheel caulk. (I was to lazy to do it, just to take a pic.
If you don't have a table, just jack it up and set it on blocks on the floor.
Next lay an 8' bulb on blocks of wood, next to the bike.
Slide a couple rubber bands over the light, then pull it under the frame and slide the other bulb through it. Then wrap another couple rubber bands around the bulbs behind the tire.
Then lift them up so they are pinching on the rim.
Support the bulbs on blocks of wood to hold them up, and then measure the distance from the bulb to the front rim on either side.
Adjust the rear wheel till you measurement is even.
If you have never had your engine out, or moved it in any way, you front and rear tire were aligned to track straight at the factory, and if you put the spacers back where they belong, the tire should be straight in the frame.
Now remove the bulbs, and roll the wheel to see how you belt tracks.
Now sit the bike back down on the ground, and check the belt tension.
I hope I'm not sounding like that guy who's name starts with an S
Anyway I hope this helps those that are not technically savvy enough to run the laser.