The belt alignment was excellent until a couple of weeks ago. No adjustment were made. All of a sudden there was loud squeaking noise that I noticed at low speed when pushing the bike forward or backward. Kept riding with no issues but put bike on stand today to check things out. The belt is no longer in alignment between the sprockets. It is so far out of alignment that the belt is twisted at the rear sprocket. Nothing had been changed with the tension adjustment bolts. It now appears that the sprockets are not lined up and it is a big distance. Looks like maybe an 1/8 inch offset or so. I can't figure out what happened. The rear sprocket is not damaged and was tested true with a flat bar held on the swingarm to check distance to the outside edge of the sprocket. My only guess at this point is that somehow the front sprocket moved away from the motor by 1/8 inch or so. This does not seem possible though. The first time the belt broke the motor side tack welded ring fell off so I had to remove the sprocket and weld it back on. It was VERY difficult to remove it and was also very tight going back on. The set screw was torqued onto the key and the the coaxial bolt lock tight and tightened onto the shaft when it was reinstalled. I don't think it could come undone on its own. Does anyone have any suggestions? Thanks!! Here (attached?) is a photo:
From the image it’s hard (impossible) to determine if the rear sheave pivoted CW or the motor sheave moved outboard (from motor).
If the former, belt tension would decrease.
If latter, belt tension would slightly increase.
The only changes made were the removal & re-installation of the motor sheave.
That’s were I would concentrate my efforts on.
Put the bike on a stand or jack so rear wheel is off the ground.
To check sheave alignment (drift), take a piece of string 3x the distance between the sheaves & wrap the center of the string once around the belt.
Rotate the rear wheel so the belt carries the string around the motor sheave edges (but is not making contact with motor shaft.
Now take each end of string and use like two individual straight edges to determine how much (if any) drift there is between the two sheaves.
Please let us know the outcome for our knowledge.