Originally Posted by cisco
I went the other direction. I changed to the 17 tooth(650 gearing), to get better fuel economy. It got worse. A friend and I went on a Baja trip, where he constantly got better mileage with the stock gearing then I. It would be nice to have a wider box. Go figure.
I would not have thought going from 16T to 17T would reduce MPG....
Any chance you can do an A<-->B (swap) test and have your buddy ride your bike and see if the results are the same? Maybe it is riding style, differences in gear+rider weight?