How much slack should the drive belt have?

[lv125403]

I have a 1987 marathon. There is a lot of slack on the drive belt, but I thought that was normal until I looked at the belt on a buddies cart. His belt has just enough slack to let the motor turn free while starting. My belt is much looser to the point if the drive clutch has to close to about half before the belt engages. I am wondering if this could be why my cart bogs down up hills. It has a new drive clutch, and when I go up a hill, the driven clutch is very close to it maximum diameter(I drove it uphill without a seat). Thanks

[rvkersh]

Make sure you have the correct belt, belt should deflect about 1 1/2" when pushed down midway between the clutches, this is normal for any cvt system. If yours is incorrect the you have the wrong belt or a problem with the secondary clutch. Make sure your motor mounts are intact, if broken the engine can shift to the secondary clutch and cause belt slack.

[BlackBerryHill]

The 1 1/2" sounds about right. I have an 18 HP v-twin, and I've experimented with various amounts of tension. Too tight and I have shifting problems, too loose and I get a decrease in performance. I just put a new belt on the other day and finally set the belt at about 1 1/2" of slack to get the best performance. It's amazing how such little variation can have such a major impact.

[lv125403]

wow, I have way more slack than that. I cam almost push mine till they touch. My engine seems to be secure, but I will check the mounts. I measured the belt and it measures right about 45 inches, which is what it calls for. I just replaced the clutch, and it is made different than the original, but that shouldn't change the at rest tension. It did make a difference in the starter belt tension though. I had to get a belt that is a half inch shorter to get it tight. thanks all