Idler gears ruined

So, i took my top end off to get to my base gasket, which has been leaking since i did a rebuild on the bike.

What i found was that one of my cam gears and the tower was completely ruined. The cam gear is in two pieces, the rubber completely torn away. Same with the tower, but it is locked in its metal housing. There is some gouging(nothing really harmful, just ugly) around the gear and in the metal housing.

How was my bike even running? And why would these gears be so ruined, they were in good condition when i finished this rebuild 6 months or so ago.

Take some pics and post them. Odd... never heard this happen. Check the condition of the front cam chain dampener... it is the one in the front of the block.

had that same thing happen to mine,but mine stop running,i took it apart and the oil pan was full of the s&!t, i figure they just wore out,but am going to buy all new parts for it ,and i hope it dont happen again,,,,by looking through my parts,i am think it could be my cam chain tensioner,am not for sure,but am replacing it to

heres a pic.

Also, has anyone had any problems with those liska billet steel ones? Thats what i am replacing it with.

Those idler gears do what yours did quite commonly. I thought you were talking about the sprocket directly driving one of the cams going bad which would be unusual. I just break into a junk engine and use used parts when these go bad. I bet the billet ones would work fine though, because the Kawasaki part is really expensive to say the least. All 3 of your sprockets are most likely bad as they all go bad the same time generally. Deterioration from heat and age.

When I got my motor apart I found my guide in the pan. I had the cylinders sitting on the bench and I put one of the gears back in. While talking with my friend I was spinning the gear with my finger and it felt a little odd. That was a bummer cuz those little guys is spendy! I have finally found one out of a low mile bike so I should be good to go next week. I feel your pain!

well, that is a relief. At least i know this happens normally.

I was just concerned i had some odd problem.

What kind of noise does the engine make when these start to go bad? I just picked up a '78 kz1000a recently, while it was quiet when I got it, it's come up with a sound that I suspect is cam chain related, clunky, pingy and somewhat rough running if you get on it even a little until you hit 3000 rpm or so, then it goes great. The bike now has about 13K, but was only driven about 350 miles in the last 4-5 years by the former owner. I've already put on close to 750 miles in the last 2 weeks.

twinkyrider wrote:

What kind of noise does the engine make when these start to go bad? I just picked up a '78 kz1000a recently, while it was quiet when I got it, it's come up with a sound that I suspect is cam chain related, clunky, pingy and somewhat rough running if you get on it even a little until you hit 3000 rpm or so, then it goes great. The bike now has about 13K, but was only driven about 350 miles in the last 4-5 years by the former owner. I've already put on close to 750 miles in the last 2 weeks.

I doubt these bad in a 13,000 mile engine. Like I said, the rubber goes bad from heat and age. You have the age, but not the heat in 13,000 miles. Mine went bad at about 130k in the 650 and my buddy I was just talking to yesterday reported his bad in his 70,000 mile 74 Z1 recently. Like anything in the world though, your mileage will vary. On my KZ650 when they went bad all it did was make for a noisy camchain you could hear real easily as being something wrong, but not any horrific grinding noise or any difference at all in how the bike ran. Have you done the manual camchain adjust that takes 5 minutes to do? This may be all you need if it is a camchain noise.

I found the front idler gear bad on a 76 KZ900 with 8200 original miles. Got the bike from original owner and motor had never been apart. Outer part of the gear had shifted sideways from the inner part of the gear and the gear was rubbing against the cylinder block. There is like a rubber sleeve between the inner piece and outer piece and this is where it had shifted. All the other gears and rollers looked like new. Don't know if this is a common problem or not.

I've heard that some KZs had a problem with there idler gears and some got a recall and others never got the recall. Some bikes would quit running 2500 miles after they leave the show room.
Probobly why a lot of the bikes found sitting for a while that dont run have little miles on them.

RonKZ650- Does the engine need to be in a particular spot ie. #1 at TDC to do the cam chain adjustment? Waiting for the big Kawi manual to show up but should do this soon.