Z1R Spat out a Shim

Hi guys, question for you.............my Z1R engine was rebuilt recently by an experienced Kawaski guy. I haven't done alot of miles on it as I have been sorting carbs etc. It started making a bit of racket so I shut her down and lugged the old girl home. I pulled the cam cover off but didn't notice anything intially. I drained the oil and a massive chunk of shim came out. Went back up top for a proper look and yep, chunks of shim lodged about the place.

Why would a fresh engine through a shim? Don't want to go to the expense of fixing it to have it happen again!

That shim hasn't been spat/thrown, It's shattered.
The main possible causes will be
1- Inferior aftermarket shim used.
2- Shim has been ground.
3 - Shim wasn't seated in the bucket correctly and cracked on assembly or on start-up ( most likely).
4 - Early type shim used ( identified by a dimple in the center of the shim) which are prone to this type of failure.
Looks like the bucket/lifter has also took a battering from the shim fragments so i would replace that too.
 

........................and all the people complaining about the 550/650/750 having shims under buckets.

All the above reasons
I would recheck and  right down all the valve clearances and then pull the cams
Take some more pictures and post them 
Cam is now suspect until  proven ok
Dave

I suggest you carefully check all the shims to see if they are aftermarket or real Kawasaki shims.  I would ensure that all shims are genuine Kawasaki shims, not aftermarket.  Otherwise you may experience the problem again on another shim. Ed

Stupid question............Looking at the photo of cam lobe and the area around the shim bucket I notice there are no signs of any oil!!!!! Usually when you pull the valve cover off a motor that has run recently a film of oil would coat the cam, and all the surfaces inside the head. And there would be small puddles of oil in the recessed heads of the cam cap bolts. I don't see a drop of oil anywhere in this photo!!!Did you spray some type of cleaner to help remove all the small pieces of metal from the shattered shim??

Not one sign of oil in this photo!!! Dry as a bone!!!
 

Notice how all surfaces inside the head have a coating of oil on them.
 

Wonder if the head was bead blasted and there was grit remaining in some of the oil passages?

wrote:

That shim hasn't been spat/thrown, It's shattered.
The main possible causes will be
1- Inferior aftermarket shim used.
2- Shim has been ground.
3 - Shim wasn't seated in the bucket correctly and cracked on assembly or on start-up ( most likely).
4 - Early type shim used ( identified by a dimple in the center of the shim) which are prone to this type of failure.
Looks like the bucket/lifter has also took a battering from the shim fragments so i would replace that too.

 

That makes sense. I couldn't tell you what shims were used in the rebuild but I will check them out. Appreciate your advice.

wrote:

All the above reasons
I would recheck and  right down all the valve clearances and then pull the cams
Take some more pictures and post them 
Cam is now suspect until  proven ok
Dave

Thanks Dave. Will do that and post up what I find. Cam lobe does have a decent gark on it now from munching on the shim bits.

wrote:

Stupid question............Looking at the photo of cam lobe and the area around the shim bucket I notice there are no signs of any oil!!!!! Usually when you pull the valve cover off a motor that has run recently a film of oil would coat the cam, and all the surfaces inside the head. And there would be small puddles of oil in the recessed heads of the cam cap bolts. I don't see a drop of oil anywhere in this photo!!!Did you spray some type of cleaner to help remove all the small pieces of metal from the shattered shim??

Not one sign of oil in this photo!!! Dry as a bone!!!
 

Notice how all surfaces inside the head have a coating of oil on them.
 

 

Thanks mate, appreciate your thoughts. Too be honest this happened about five months ago and the bike has been sitting on the bench since then. I packed a small wobbly with it and have only just decided I really need to sort it out. I also got in there with the rag and cleaned out any remaining residue to see what was going on. Good call though!

Looks like one valve was tight by the base circle on the cam. 
Steve

wrote:

That shim hasn't been spat/thrown, It's shattered.
The main possible causes will be
1- Inferior aftermarket shim used.
2- Shim has been ground.
3 - Shim wasn't seated in the bucket correctly and cracked on assembly or on start-up ( most likely).
4 - Early type shim used ( identified by a dimple in the center of the shim) which are prone to this type of failure.
Looks like the bucket/lifter has also took a battering from the shim fragments so i would replace that too.

 

We've never seen shims with raised nubs on them, although true 'dimples' are likely the result of shims used on early Z1 buckets.
 
Early production Z1 buckets had tiny raised 'navels' (just a thou, .001 or so in height, maybe less, and 2mm or so dia.) centered in the shim recess due to the way the shim recesses were machined.  That loaded the shim in weird ways, essentially 'rocking' the shim over the navel in the bucket as the cam ramped up & down, leading to stress fractures of the hard,brittle shims.  Mama Kaw issued Service Bulletin "SER 73 Z-13" (6/21/73), a recall to replace the incorrectly-machined buckets with smoothly-machined buckets on both new, un-run crate bikes in inventory and bikes that had been run.

  A shim that has been used in a bucket that has the 'navel'. can be identified by a brighter & well-defined wear mark about 2mm dia., dead center of the shim.  Mama Kaw specifically indicated in the bulletin that shims that had been run in the early buckets be discarded.  However, it's not uncommon for us see on shims we've taken out of service in later Z1's and other Z-bikes the 'navel' wear marks, so the damaged shims were sometimes reused or re-sold to unsuspecting buyers.

We've not seen any early, recalled buckets in any bike after, say, mid-production Z1-A's that had the factory OEM buckets in them.  A Z1-R should certainly have the correctly-machined buckets provided that the buckets are original.
 
Good Ridin'
slmjim & Z1BEBE