I also experience motivation problems. For me, the problem is that riding becomes too routine. The same roads and routes, the same scenery, the same weather issues. What I do to combat these disincentives is to add as much variety as I can to my rides. I have three very different bikes to choose from, a tourer, a road bike, and a single speed. Each offers a different kind of ride. In addition, I try as much as possible to ride streets and roads that are a little out of the way. I also vary how I ride, sometimes fast (single speed), sometimes varied terrain (road bike) sometimes just tooling leisurely along (touring bike). I try to ride every other day, but weather here in Montana does not always cooperate. I don't ride when it's very windy or stormy or wet. I also ride alone, which makes it easy for me to satisfy whatever riding whim I might have on a given day. I usually feel great after a a typical ride (20-30 miles), so I tell myself how good I will feel when I'm not in the mood for riding. That sometimes helps. But my love for being on a bicycle is my greatest motivating factor, which I have to keep reminding myself about.