1980 KZ 250 with a Keihin CV32 carb. Bike won´t rev past 4000 rpm. It gets there and just dies. I have cleaned the carb, adjusted the timing and valves. Everything is clean. The bike idles great but when I throttle it up to 4000 rpm it just dies. The main jet is clean and the bike used to run great. I let it sit for two years, but have since cleaned everything. Is there some passage in the carb I am missing when I cleaned it?
I just did a test on the carb by putting a vacuum to the engine side and opened the butterfly valve. The piston behaved as expected, it was raising and lowering as I opened and closed the butterfly, and gas was shooting out of the main jet in a fine mist. I have adjusted the float level to the factory reccomendation and there is a new plug. I am completely stumped? Any help is appreciated