Hi everyone. I've been lurking around a bit and can't seem to find my particular issue. I have recently acquired an '81 cb650c. The bike is in excellent condition, and seems to have been loved by someone recently. It has the classic power-loss-at-high-revs issue and I am currently working through from easiest to mor difficult checks. Thanks to everyone here for a vast wealth of knowledge on that subject.
So it fires up easy and idles pretty well (after some adjustment). However, it doesn't seem to care how open or closed the choke is. I pulled the rack off to check the function of the butterflies, and after a little messing around, got the butterflies working properly (they were sticking slightly and not closing all the way). I put it all back together, but it still behaves the same. Whether the choke is closed or not it performs the same. The obvious answer is an air leak, but I can choke the air filter by hand and get the expected result.
Any help would be greatly appreciated.
-Obie
