Drive Belt Problem on Frankenstein Trike.
I'm on a Frankenstein Dyna Wide Glide, but my first thought is the rear axle alignment. To set belt tension the bike has to be on the ground to properly set the belt tension and rear axle alignment.
To adjust the alignment and belt tension you work from the drive line side; the right side on a Sporty in your case, with the four rear mounting bolts loose. The drive line side adjuster nut is first tightened to factory belt deflection spec; tighten the jam nut on the adjuster, then on the opposite side walk the adjuster up to the spacer so it's in contact with the spacer, then tighten the jam nut. From there you torque the four rear mounting bolts to 60 ft-lbs.
The simplest way to explain it, is to hold your arm out; small movements at your shoulder are much more exaggerated at your fingertips; if your rear axle is out of alignment that will position the drive belt at a different position on the transmission pulley.
In the case of my Wide Glide I know the belt tracks slightly inboard on the transmission pulley, once I did the conversion; the rear pulley still tracks true, to the left side. My first thought in your case is your rear axle alignment is out of spec allowing the belt to walk off the transmission pulley. Did you do the conversion yourself, or have a dealer/indy do the job? The rules in the service manual go out the window once you trike your ride
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It's very easy to get the rear axle slightly cocked when adjusting the belt tension and that can cause the belt to walk off the front pulley. You MUST have the full weight of the trike on the ground when checking the tension.
After I had the tension perfect I held a long straight edge (5 foot tubing) on the center of each rear wheel (needed help from the wife to hold a straight edge on one side) and discovered the axle was slightly cocked when the straight edges were compared to the front wheel which was held in perfect center by concrete blocks.
The left side needed to be tapped forward just a tiny bit and tightened down. After that I raised the rear off the ground by raising the bike and the rear the same amount. I spun the axle in both directions and the belt stayed where it belonged. Rechecked the tension and it was still OK. After a test ride it still remained where it belonged.
Sounds like a lot of monkey business but like Tin Cup said, you have to figure out a lot of this stuff yourself.



