Ok here's the latest:
I installed the K&N and it barely runs. Lots of smoke, no power. I tried turning the adjusting screw on the carb but it doesn't help. Any ideas?
Some possiblities:
Float level too high. Just a bit of extra restriction with a freshly oiled K&N may be causing it to pull too much fuel.
Way too much oil on the filter. Rinse it out with gas, then mix some oil with gas, about 60% gas/40% oil, wet the filter with it, then let it dry for a few hours to get rid of the gas.
I've also heard of K&Ns causing a problem on some bikes - the blowback of air/fuel through the carburetor catches in the filter, then gets sucked back into carb on next stroke, but that's usually on race bikes with pretty wild intake timing.