I had tried using the Link Belt a long time ago of various brands and it was slipping bad. I did though change to a cogged belt on just one pair of pulleys that had one very small like 2.5 inch diameter. I thought it would help. I have tensioner of back idler and movable jackshaft for adjustments. I eventually went to gear and chain on some of the tranny. The drive sheave like I see you have on the rear wheel is like mine. I only paid like 45 dollars for it. I finally found that the pressed steel sheave as it is bent and made circular, had a butt joint weld that had a bump. Aside from it being able to adjust to get better centered, the bump I eventually fixed with A Dremel Grinder and then sanded by hand with emory cloth. It was an amazing difference. If water gets on the pulleys and belts then until it dries it has adverse effect. Dust not so much, but oil fumes I clean the sheave with acetone and wash the belts with dish wash liquid and then dry occasionally. I ride though streams doing trails is how I found out, but that is not all. Rim brakes are no good for a while too, which is dangerous to note. From that point just now if I go up too steep a grade I have no slipping, just I could burn up a centrifugal clutch I have. The steeper slopes I could deal with better if the 12:1 ratio ending up on 26 inch rear wheel were switched back to 20:1 ratio. I plan on doing that as I had before a 20:1 ratio, only when swapped in another Briggs engine that was less worn out it would not work the clutch. It is since the current Briggs has a stubby crankshaft that will not permit enough length for my centrifugal belt clutch. The gear tooth clutch does not need as much length. Belt clutch on hiatus the last few years now. I may one day open up the engines cases and swap the crank shafts if they are compatible. As Tony said I could also raise compression, shave head some, port, and the like for more power. Thinking a mfr trail bike but is harder to transport legally. My registration got Spec Constrc for use as MC only OHV. Your machine has a charm to it and the tank like that beats my rotary mover plastic tank by far.