Top end is gone below 70º

Today was overcast, damp and chilly, perfect weather for a ride except the bike ran like crap. When it's above 70º the China Girl runs like a dream, I'm hitting 25 and not even at WOT just minutes after staring her up cold in the morning. Today it was barely 60º and damp, I had to hold the throttle wide open to maintain 25 and on a downhill run that I've hit 32+ going down I was only able to hit a top speed of 26 and it was like the engine was losing power, back off the throttle and the power would come back. On warm days it doesn't act like that until I'm above 30.

Should I move the clip on the needle down a notch and run a little richer now that it's getting colder?

Cold enough that as soon as I found civilization again after getting lost for an hour I had to stop for coffee. lol

Already using Opti-2 @ 100 to 1 so putting less oil in isn't an option. Low end is exactly the same, pulls right up but then just hangs at 25, let off the throttle at all and the speed starts dropping off.

I'll try dropping the clip a notch and see how it runs tomorrow since it's supposed to be another crappy day.

Well with opening up my muffler a bit (see silverbear's glowing muffler thread) and moving the E clip to the top notch seems to have fixed this. Rode 54 miles in 60º weather and it ran great. Even finally broke in and smoothed out 10 miles into that run.