Thanks for the great info.
Right now my bike is my main transportation, so I can't really tear it down and study it. Rather, I'm trying to go after any problems bit by bit, during my lunch breaks and in the evenings after work...
My airfilter element was already presoaked with oil when I bought it new, and I cleaned it with carb cleaner trying to get rid of the 4-stroking problem. We sell K&N airfilters for cars at the VW shop I work at, and they come with a can of oil to treat them with, but I have no idea what kind of oil it is.
Since installing new jets and reinstalling the aircleaner element yesterday, I've put about 40+ miles on the bike. It is running much better now.
As far as mods go... With the small wheels and short wheelbase, it goes as fast as I'm willing to ride it, going downhill. Any faster and I'd be afraid of it. There are a lot of hills between work and home, and if there's any kind of headwind, my speed can drop to as low as 10-15 mph going uphill. Taking off from a traffic light on a hill can be kind of embarrassing, too. Holding the hills is all I'm really after. I guess what I'm interested in is more torque, rather than more top end.
I built a larger than stock engine for my '67 VW bus last year, not so I could spin tires or show off, just so I could keep up with traffic. My '84 QT is the newest vehicle I own, and I baby all of my machines.
Anyway, thanks for the help. I'm sure I'll have more questions for you later...