My 2009 Voyager with 10,000 miles had been running fine until one morning when I started it to go for a ride. There was a LOUD clicking coming from the top end of the front cylinder. Using my stethoscope, I isolated the noise to the exhaust valve. It sounded a lot like a solid lifter that was WAY too loose! I guessed that the hydraulic valve adjuster was not functioning properly, and I shut it down. After a bit I restarted. Same noise. For several days I started it several times, heard the noise, and turned it off. I decided to take it to the dealer (it is in extended warranty), but was worried that Kawasaki might use all the performance changes I made as an excuse to refuse to honor the warranty. Two days later I had it back to stock and ready to keep my service appointment. When I started it to go to the dealership, it clacked a few times then the noise stopped!!!!!!!!!!!!! I changed the oil and filter figuring that maybe something floating in the oil had clogged a passage in the lifter mechanism. It ran fine for two weeks. Then one morning it started the exact same noise, but on the rear cylinder! Slightly perturbed , I proceeded to start and shut it off several times, and the noise stopped as suddenly as it began. It was as if the lifter had pumped up and closed the clearance. It has run fine for a couple of weeks now, but I am concerned since I really do not know what caused the problem. Taking it to the dealership while it is running fine is probably a waste of time since the oil pressure is building and the light is going off as soon as the engine starts. Hard for them to diagnose something that they can't hear. I would appreciate any replies from people with a similar experience or with suggestions. I am at a loss.