posted this on the Dyna forum-got one intelligent answer and one not so much so thought I'd try it here.

My drive belt is rubbing on the inside of the upper belt guard. At first I thought it was because it has lowered shocks ( Progressive 11" ) since I can see where the bottom edge of the fender was hitting the guard. I clearanced the bottom of the fender and put some tape over the scar to see if it would hit again. It did riding two up so I clearanced it some more, marked the belt, and took it out by myself.

No marks on the top of the belt guard this time but you can see by the fresh crayon mark that it's still rubbing the guard. ( Add: second time out it did hit the guard but the guard is still not bent out of position).
My suspicion is the belt is flapping enough to do this but why would it do that? Wrong belt tension? Tension seems ok according to the posts I have read here re belt tension.

As heavy as the guard is and as far away from the belt as it is it seems like it would really show some signs of being bent if it was that far out of whack but it doesn't. (Add: it was a little bent-I fixed it but still rubs. ) It was like this when I got it and has been that way long enough for the scar on top of the guard to have a little rust where it went through the chrome.

Thanks in advance for any ideas on this.

 

cant really tell, but wondering if someone has changed the rear pully. It looks chromed, why I wonder it its a mod.

If so it could be a little bigger in DIA. for more low acceleration. thus causing it to rub.

 

Pulley just has a chrome cover on it but a friend also suggested going to a smaller pulley.

I noticed last night that the belt is also hitting on the primary case where it enters. I'm going to hunt up some stock length shocks. It has 11" progressives on it which I think are causing most of the trouble.

 

The Belt is 2 Loose,
with the bike loward The belt needs to be a little tighter

 

I just went out and gave my Dyna a good look. I can't see how lowered shocks could cause the belt to rub on the guard. The guard is attached to the swing arm and should be the same distance from the belt no matter what you do to the shocks. As for the belt hitting the primary - I can't see how that could be either. I have a ton of clearance there. I can't think of anything that could cause that except having a larger than stock pulley (or possibly a larger front sprocket) on the bike or the belt is way too lose.

 

Have you checked belt tension with a gauge? A rule of thumb is that you should be able to twist the belt about 45 degrees.
I'm not too familiar with Dynas but could worn or soft bushings and mounts (swing arm and/or engine/trans mounting) allow the belt to loosen up under load?

 

I'm going to buy a gauge this weekend. Tightened it up last night as it was pretty loose and didn't see any more marks on the guard after a test ride. But it has been rubbing for some time before I got it. I've had it a couple of months and noticed it then but didn't know enough at the time to investigate further. The bike has a few issues that need to be resolved obviously. I could have probably done a little better had I been more patient but this popped up for sale in my price range and I wanted to ride now.

good question about the mounts-hadn't thought about that.