Rebuild Question- Valve shims (?)

Hey guys, first post here. I was referred here from a few people, and have been browsing around for a little bit now. Happy to be here.

Anyways,I am in the process of rebuilding my dads 76 KZ900 A4 which was sitting since '87. Long story short, when I pulled the head off and all the good stuff, these "caps" fell off from on top of all the valve springs (i didn't know they were even there, so they fell out when I turned the head upside down). I don't know where they go now, any help? I don't have them right in front of me, but they do have numbers on them that are like "275A"..."270"..."265A".. etc. I only need to get the head on and I will be good to go, but I'm at a dead stop until I can figure these caps out (are they shims?) Any help would be great.

Welcome to KZr cuddies.

Yep, those are shims, and are supposed to go under the buckets that the cam lobes ride on.
Hate to be the bearer of bad news, but you're going to need to figure out which valves those went to AND measure the clearances to do a proper valve adjustment before you should even consider trying to start the engine. :S

Hi ,Welcome ,

OK DON'T freak out ..........
Its not easy ,BUT its NOT rocket science either.

On a stock KZ900 the shims go on top of the buckets ,
with the #'s DOWN.

The #'s are how thick they are in MM.

If the head if off just do 1 cam at a time and set them on the bench .

You MUST put shims in ALL 4 buckets before you put the 1 cam in .

Once you get that cam done to spec.
pull that cam and shims and buckets and put them aside.
WITH EVERYTHING IN ORDER SO IT CAN GO BACK WHERE IT CAME FROM .

Now do the other cam the same way .

You will no doubt have to trade off the last few shims for the right ones ,

But this should get you started.

PS watch out with the cam bearing caps ,
put them back in the same place and be careful going over the dowel pins .

If you haven't done so already, buy a Kawasaki Heavy Industries shop manual (available on eBay and reasonable)...the only way to disassemble/reassemble a KZ.

I would assemble the head on the bench without the valve springs but after installing the cams. Select cam followers that fit and move smoothly in the bores and then select a shim for trial. Naturally when trying any valve the valve itself has to be pressed hard up against the seat with your fingers and the cam lobe 180 deg away from the shim. This is much quicker than working with the head on the bike and gets you in a position that when the head is fitted the engine should start. Reassemble head with valve springs and place on bike. Once valves timed go over them once more checking that clearance are within spec.

Welcome... being a clutz, I do the same sort of stuff all the time... no big deal but it will take some work to get the shims back where they go. PLUS you more than likely wanted to check valve clearances anyway and the shims in there now may not be right. You can get a shim tool and a shim "kit" or the individual shims from www.z1enterprises.com - If you need help checking valve clearances, here is what I would do...

stick any shim on any bucket. Then go to our website and have a look at the "Valve Clearances" tech article under "wg's Tech Stuff Index"... our website is www.wgcarbs.com

I would also consider disassembly of the cylinder head. To do this, you have to compress the valve springs and remove the split keepers. This is done with a valve spring compressor and a magnet basically. These tools may also be available from the same source noted above ( www.z1enterprises.com ). Once the head is disassembled, I would inspect the guides, replace the valve stem oil seals and lap the valves in after cleaning the valves and combustion chambers. This is just a maintenance item as far as I am concerned. Once you have done it once, it is a 2-3 hour job. The guides are hard to measure with a very small bore gauge and I find it best to insert a valve (after head is disassembled) and rock it in the guide to see how much play there is. That works as well as trying to measure the roundness and diameter of a 7mm hole.

Thanks guys for the help.

I already rebuilt the head, took all the vavles out and cleaned them up (bike only had 4,400 miles on it). I ordered new stem seals and got those popped in. Grinded the vavle seats and did all the good stuff. Valve springs were taken all off and all measured, and are put back together now; so like I mentioned, I am just waiting to figure these shims out... LOL. I am rebuilding this in a Auto ROP class with my instructor helping me.

Anyways, like I said, I don't know what place each of the buckets and shims fell from So yesturday I mic'd all of the shims themselves, and this is what I got..

"275A" = .109 (thousandths)
"270A" = .1065
"270" = .1065
"265" = .1045
"260A" = .102
"260" = .1025
"240A" = .0955
"235A" = .092

What is the difference between the typical numbered ones, and the ones that have an "A" after?

FWIW, all of the "shims" are still with the origanal "caps"- those have not been mixed up.

Thanks guys for the help.

I already rebuilt the head, took all the vavles out and cleaned them up (bike only had 4,400 miles on it). I ordered new stem seals and got those popped in. Grinded the vavle seats and did all the good stuff. Valve springs were taken all off and all measured, and are put back together now; so like I mentioned, I am just waiting to figure these shims out... LOL. I am rebuilding this in a Auto ROP class with my instructor helping me.

Anyways, like I said, I don't know what place each of the buckets and shims fell from So yesturday I mic'd all of the shims themselves, and this is what I got..

"275A" = .109 (thousandths)
"270A" = .1065
"270" = .1065
"265" = .1045
"260A" = .102
"260" = .1025
"240A" = .0955
"235A" = .092

What is the difference between the typical numbered ones, and the ones that have an "A" after?

FWIW, all of the "shims" are still with the origanal "caps"- those have not been mixed up.

Hi, since you ground the valves, your clearances are going to have changed, no matter what shims were where. The buckets should be interchangable.

It sounds like you already have the valves resprung and in the head.

I think you could roll a cam around so the lobe is away from the bucket top, and use a vernier caliper probe to measure the clearance between the bottom of the lobe and the top of the shim bucket.

what it is, here

Here is a link to show the scale and how to use the measuring part of the caliper.

Caliper activation

You would use the probe, at the end of the caliper, to get an entire gap measurement, subtract out some for clearance and then use a shim to represent the difference.

Should get you in the ballpark.



Post edited by: KaZooCruiser, at: 2007/05/09 12:33

KaZoo, I did not lap the valves, therefore no actual valve measurements have changed. I tore the head apart (pulled the vavles and springs), and while it was apart, I cleaned the valves (decarboned them), replaced the valve oil seals, check the spring tensions, and ground the valve seats- then reassembled. So technically, the only thing that CHANGED was the oil seals. That is why I am just trying to figure out what the stock (or like) placement of these shims were, so they could go back into where they belong. Nothing on the cam has changed either.

Sorry if I have been unclear about anything!

Heres a few pics to give you a clue as to what I'm working on. I'm just tryin to make my dad happy .



**(I am not sure if HTML or [img] coding works here, so I will post both). **Here is the bike before I started working- after damn near 20 years of sitting.. [img size=550]http://i70.photobucket.com/albums/i88/erik250/Picture118.jpg[/img]



**Cylinder and Head right after I took them off (The piston were stuck btw, took about 45 min to break them free..)




**Motor once it was apart. Really dirty






**Heres the carbs. They were stuck, too. Took about 4 hours to get them all apart, let alone rebuilt..




Then I got a shipment of all my new parts, started going back together..

**Got the carbs rebuilt, and some filters.




**Throttle Body attached to head



**Motor all cleaned up and ready to go back toghter. I was excited when I got to this point LOL







**And they FINALLY move niceee!....
s70.photobucket.com/albums/i88/erik250/?...=view¤t=MOV00008.flv




Sorry if I bore you with my progress. I am just very please and very happy at with things are coming along, let alone putting a smile back on my dads face after sitting for 20 years.

Post edited by: kzrider, at: 2007/05/09 17:13

KaZoo, I did not lap the valves, therefore no actual valve measurements have changed. I tore the head apart (pulled the vavles and springs), and while it was apart, I cleaned the valves (decarboned them), replaced the valve oil seals, check the spring tensions, and ground the valve seats- then reassembled. So technically, the only thing that CHANGED was the oil seals. That is why I am just trying to figure out what the stock (or like) placement of these shims were, so they could go back into where they belong. Nothing on the cam has changed either.

Sorry if I have been unclear about anything!