Now that I'm retired... Chasing old bikes doesn't stop. About 4 months ago, I picked up 1984 Kawasaki GPZ 750. Hack hack bang bang and it's running. I originally tried to use original air box. Those rubbers were rock hard as one would expect so I trashed stock air box. These are CV carbs. So when it was first running on the center stand it would ran and rev great.. Then I took first ride.. Twist the trottle and no power. No big deal. I'll drill out the main jets. Done it tons of times on other bikes and it works great. Did a number of CB 750's with pod air filters like this. So I drill the main jets and got it to run fine. So it's a great little quick ride up to about 1/4 throttle.. Turn throttle wide open and it's like someone turned off the ignition. There is NOTHING. Not a flat spot that I can get past. There is just nothing... Fiddled with it for 2 months...but it wasn't a priority. The bike is a beast with just 1/4 throttle. So I drilled jets more. No change. I fiddled with restricting air flow into the pod air filters. Nothing seems to let this thing run at full throttle. There are 4 slots to adjust needle jet. I've been on the top and bottom slots. No change... Actually I'm perfectly fine with just 1/4 throttle cause it will spin up to 90 or so in a blink of an eye. It's actually becoming a matter of pride that I can't seem to make this thing run at full throttle. I'm sure someone here has done similar battle with CV carbs.