I just passed 2000 miles on my bike and thought I would give a report how it has held up. I dropped the gear ratio to 13.65 to one because the 12-1 needed help on a couple of hills when pulling a loaded trailer. The top speed dropped to a little over 35 mph and can't tell any difference in gas mileage.
The primary chain takes a lot of lubrication to make it last. I have to oil it about every fifty miles. I am thinking about changing to a belt drive for the primary. The chain speed is just too high at the speeds the engine turns but it will last if it is kept lubricated.
The bike has never failed to bring me home but came close one time. The rear wheel slipped forward, probably because I didn't tighten it properly. It threw the secondary chain, broke four spokes and bent three but the wheel stayed amazingly true, enough to take me five miles home. It also bent the disc brake rotor that I had the sprocket mounted on. I couldn't find a new one so made an adapter from 3/16" steel. Works fine and won't bend.
Also found a great chain oilier at the heating and cooling place where I sometime get parts for a job. The oil is o.k. but I will try chain saw oil in it when it runs out.