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2003 z400 loud knocking noise?

6K views 6 replies 5 participants last post by  jetmech25 
#1 ·
So to start off my 2003 z400 just started to have a knocking sound in the engine. there is at least 10 hours on the new crank shaft and bearings. Also new piston along with new jug. I dont think it could be piston slap. you can hear the knocking noise when its idling or reving. Could the bearings on the balancer be going out. Also we just had a valve keeper break and it bent one of the exhaust valves. Its had about 2 hours on it since then.
 
#2 ·
it would not surprise me a bit that the cage that holds the balls in the bearing has come apart. BTDT
 
#3 ·
i just took the clutch cover off and found a backed off nut on the counterbalance gear. I took the gear off to find a that the key was moving back and forth and created a big groove in the counterbalance. Could my knocking noise have just been a timing issue since the gear was sliding back and forth.
 
#4 ·
Most likely the counter balancer weight was smacking something like the crank. They are timed and spaced pretty closely.
 
#5 ·
I had the same issue with my ltz. Turned out it was just the timing chain adjuster. They had a really pour design and it doesn't let you adjust them far enough. I got on amazon and ordered a aftermarket one with a little more adjusting available. put it on their and tighter it correctly and I haven't had a problem since. It could also be the timing chain being to worn out. If that is the issue you will have to tear into your motor to replace that.
 
#6 ·
what my knocking looked like
 
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#7 ·
Seems to be a couple of balls missing! ?
 
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