Engine Knock

Good chance it's a gummed up cam chain tensioner. Those Hyvo chains will sound like a rod knocking when the tensioner screws up.

Pull it, take it apart, clean it, sand the plungers with some 1000G paper to debur them.

The springs also sack out over time. APE has an aftermarket manual adjust unit that cures the problem once and for all.

Larry C

I had a loose alternator rotor that made such a racket I could have sworn it was a rod knocking. The sound would come and go as you described, I was not able to figure it out until it loosened up a little more and trashed my stator.
As was said above get a mechanics stethoscope and you should be able to determine the source of the noise. Good Luck

Will add the cam chain tensioner to the list of possible culprits!

I'll go with the piston slap as you're noise.
Have you done a carb sync while engine is at temp and running? If the offending piston is getting a stronger signal than the others it may amplify the noise.
New springs for the cam chain tensioner are available from Kawasaki, around $18 for the 2. There is also a O-ring here where the tensioner bolts up. Remember to turn the motor to TDC 1/4 mark before removing tensioner.You can do this at the same time you look for your oil leak at the cooler hoses etc.

Thanks Motor Head. Will add to my list!

Motor Head wrote:

I'll go with the piston slap as you're noise.
Have you done a carb sync while engine is at temp and running? If the offending piston is getting a stronger signal than the others it may amplify the noise.
New springs for the cam chain tensioner are available from Kawasaki, around $18 for the 2. There is also a O-ring here where the tensioner bolts up. Remember to turn the motor to TDC 1/4 mark before removing tensioner.You can do this at the same time you look for your oil leak at the cooler hoses etc.

maybe this above fuel/carb idea makes the most sense to an idiot like me.....i would think a rod or bearing or piston slap would act up at stop signs and creeping along in traffic...or leaving a dead stop when warm...i would think a cam chain/tensioner would act up when you close the throttle and start gearing down /clutch in-coming to stop lights (or while idling in neutral after warm,,,does it pop or stumble when warming up a bit from overnight off...what do the plugs look like....almost sounds like a fuel starve on a cylinder for a flash then clears and carbs correct...

total idiot here but...the sound you describe reminds me of forgetting to turn my gas on while running errands after a stop....as it just starts to stumble it knocks...