Michael wrote on 12/31/69 at 16:00:04:Even though you can adjust the belt with the adjusters, and have it perfect tension, and balance, tightning the axel nut throws it off again, and even makes the belt tighter.
The secret is, leave it a bit slacker than you want to, before tightning. I also found that letting the belt run on the left side of the pully by a hair, will center it after axel nut is tightened.
I have sat back through this subject, but now I need to add my 2 cents. People just tend to spend too much time stressing about the rear wheel. It isn't their fault, but it isn't that complex.
1. Starting with the belt loose, another trick is to leave the axle nut "snugged" on the adjusters and then use the adjusters to pull the belt to the desired tension. They will pull the axle when it is still snug (snug = about one turn from tight).
And then you only turn the nut while holding the axle bolt stationery with a second wrench. This keeps the bolt from "walking" in the swing arm hole.
2. And I think this whole "belt alignment" issue is a bit over worked. Just for speculation, let me ask "Why is there no mention of such a detailed process in the MOM or the SSM?" Answer: Because the alignment isn't that critical. The belt will always rub slightly on one side or the other of the pulley, no matter how much you mess with it...
It is simple mechanics...If you reach down and grab the pulley you will see that it will move from side to side even with the axle tight. This is because of the play in the drive bushings and the internal slop in the pulley bearing. As well, there is only one bearing in the pulley, and one bearing can never be perfectly rigid (the wheel hub has 2). Look at the picture below...all the spacers ONLY position the inner bearing races on the axle bolt. If they positioned the outer races, the wheel wouldn't turn. What we have is engineered play in the pulley and out at the belt diameter the play is magnified So with this movement, it is simply impossible to get the belt to track dead nuts in the pulley.
Just position it equally on both sides with the stamped marks on the swingarm and go...
3. I believe that the "belt tension" issue is also over done. New bikes come with a gage but for those without a gage they use the "90 degree twist test". Neither method is rocket science and that's because the only critical factor is having the belt
loose enough. Fact: if the belt is too tight, it squeaks, whines, and chirps.
And concerning the idea that the belt gets tighter after it is adjusted...you should simply adjust the tension with the wheel on the ground with the bike vertical (2 x 4 under sidestand).
Why? I have 2 answers:
1) You don't ride it that way. In
normal operation the wheel is on the ground

2) Geometry....the 2 centerlines created between front pulley and the rear axle
and the swingarm pivot and the rear axle are not exacly on the same axis. When the swingarm moves up and down those 2 centerlines do not follow the same arc. Plain and simple. The 2 pivot points are not the same so therefore as the shocks are compressed, the belt gets tighter. When you sit on it, it get tighter!!!
So here's the scenerio...You jack up the bike with the wheel off the ground, adjust the tension ever so carefully, and when you set it down, it is suddenly too tight. OR you don't notice and you go for a ride and it squeaks. What happened?
It is a misnomer that the tension should be adjusted with the wheel off the ground. The swingarm needs to be more horizontal which puts those 2 invisible centerlines more inline.
Summary? Adjust the wheel alignment equally with the adjusters and adjust the tension with the wheel on the ground using the gage or the 90 degree twist. Start bike and ride.

PS - if you really wonder about the pivot centerlines, just look at serious motocross bike that runs a chain. They run without tensioners and with the chain loose. Why? because they are engineered with the sprocket and swingarm pivot very close to the same centerlines with the rear axle....you can't have changes in tension with a rear wheel that may travel 10 inches or so. Right?