You have an intermittent fuel delivery problem.
Fubar the Seafoam crapola, get to the problem.
Most likely there are one of two causes...
1) IF, and that's a BIG IF, you have not jerked around with the carbs and you've got a bike with a few years (regardless of miles) there could either be a float problem or a needle valve problem. Most likely, needle valve. Small part, $8.00 at Kawasaki, but a full teardown of the carbs required. How to determine??? You need to proceed to the next step first.
2) Next step...air cutoff valve...no, it doesn't cut off air, but from the front cyl there is a vacuum line running up to the fuel petcock. First, disconnect that vacuum line and apply some vacuum (suck baby suck). Is there a positive seal or do you just get an airry gas taste in your mouth while the vacuum goes away(you can also do this with a manometer and a vacuum pump and avoid the lovely taste of fuel, but why would you ask me for such insight?)?
3) IF there is an obvious lack of suction/vacuum, please don't talk to any females about the problem. Do try the test again with a NEW pc of vacuum hose.
4) New vacuum hose, no seal on the tongue?? The air cutoff-valve is FUBAR. Temp fix, get some solid core gasket material from any auto parts store and cut a gasket to seal off the petcock. Five minutes tops, but keep the holes for the screws really really tight on clearance or you'll wind up with a leak...and then fire...and then an insurance claim... and loss of stuff that us guys like to have handy for those meaningful meets.
Now, if you got past part two and all is well, then you're screwed. The needle valves are bonkers. Pull the tank, etc and rebuild the carbs. Sorry bout that, but it's the only true explanation.
How do I know? 84,700 miles on an 86 and over one million documented miles on two wheels.