After a long absence I return and find another interesting thread. Dammit, I went your route with my '79 CB650 - up one in front, down two in back. I don't recall gaining fuel economy, but do recall having to shift into fourth on hills and into headwinds. The carbs were adjusted, synched, fiddled with, valves set, eventually the engine rebuilt. It wasn't until I returned to stock gearing that the old girl came to life again. My changes had dropped the engine out of it's torque peak at highway speeds. Now it'll hit the ton without much trouble, the clutch doesn't have to be slipped off the line, and driveability around town is much better. Of the other hints given in this thread the one about making sure your battery is good is . . . ummm. . . good. A time or two I've been caught out with mysterious engine problems - missing, sometimes backfiring, won't run beyone 5K rpm, etc. It all clears up with a fresh battery. Every few years it seems a new one is needed. They'd most likely last longer with a little more maintainence, but I'm a slob that way. As for o-ring chains, there's one on my bike. I did have to use a Dremel tool on a couple bosses on the cover plate. It cleared the engine cases just fine.
Dang. Writing this is making it hard not to go ride. But it's two AM, 15 degrees F, and snowing. Guess I'll just go to bed until spring.
