KZ900 valve shims Machining

I had to deliver 2 valves to a machineshop last winter after i cut 2 of the  valveseats to deep, but had to because of pitting .Usually i do most work myself,but  did not have a valve stem grinder so had to deliver them to a professional.
By the way  it is not good grinding shims .They can be too thin and later crack when in use . i think that also stated in workshop manual but not sure.
Anyway here is from when i got 2 valvestemend  grinded: www.kzrider.com/forum/2-engine/619343-ne...1976-kz900?start=192 I
 

Ditto what everyone is saying. Things that might be useful though. Check the top of suspect valves, look for some manufacture markings. Aftermarket ones tend to be longer overall length. One shown with marking is a K&L, stock valves are smooth as shown next to it. Also note spring keeper style, Very important!! Don't want to match the original "square" keepers (2 per valve) with round milled valves. I always use the later 77-up KZ1000 round keeper valves, intake and exhaust, when doing Z and KZ900 heads. They might of "faced" the valves too much, look for a sharp/missing margin. The tool Crazy showed is super handy and number 1.110 stamped on top is the stock base circle of all the KZ camshafts. You have to remove valve seal and valve spring seat to use it, sits flush on casting in valve bucket bore. This allows approx 37.25-37.95mm valve stem height above bucket bore floor. Within that approx .7mm range comes your shim selection. You really should have a machinist capable of doing the "final height or tipping" the valves if You're not capable of doing it yourself. They need all your stuff to properly do it          

Kaw-boy 900 wrote:

The machine shop contacted does not do the final valve ajutments.  They asked to bring the head and valves without springs. They need the actual valves gaps and shims installed.
Valves stems will be reduded so normal shims can be install. 

My concern is with the actual shims machined at 1.5 to 1.7 mm and 2 x thight valves at .038 mm / .0015'', So how much stem can be reduce ? (Kawa spec is:  be sure to leave .16'' / 4.1 mm)

Firstly ... Anyone who knows what they are doing with these heads doesn't really need anything other than the valves and the stem height required so i would go find another shop or mechanic that does...

Secondly ... The maximum you can tip the stock untouched valve stem with stock retainers etc is 0.3mm but this would barely get you to the minimum sized shim.

Thirdly ... The main choices you would normally have is to try new unworn valves to see if they get you sufficient clearance, fit bigger valves which use the wider unworn portion of the seats, use J type valves which have a 1mm shorter stem and finally the last resort would be to have new seats installed..

However there is one more alternative which i regularly employ which will get you back into a usable shim range with your current valves and retainers etc.
The stock steel retainers and collets can be safely skimmed by up to 1mm which allows the valve stems to be tipped up to a further 1mm beyond the 0.3mm specified in the manual.
This will get you back into the high shim range and many more years of adjustment especially if you can get close to the minimum stem heigh of 37mm.

First pic shows a valve set i've recently skimmed and tipped for my latest turbo build which has put all my shims in the 300 range and the second pic is of my own stem height gauges which are sized individually and are easier to set than the split height go/no go style of the APE item.

Cool stuff ZED! I mentioned bringing cams and ALL the bits because he said of taking it to a Harley fella, they surely wouldn't be familiar with this design and the fractional "tipping" required. I always do my own final clearance work here too because i can match everything according to what my shim selection contains. Question though i'm not really sure of? Why the 300 range?    

asphalt900 wrote:

 Question though i'm not really sure of? Why the 300 range?    

I really never understood why Kawasaki recommended setting the stem height for shims in the mid range.
It makes no real sense and only shortens the period to where you would run out of adjustment and require the head off for further work.
Max stock shim thickness is 3.20mm so why not aim for the lowest stem height and the thick end of the shim range from the get go if you can.
As soon as you run a fresh cut valve and seat they usually settle and require the next size down anyway.
You could understand why they may have gone safe around midrange on the assembly line to allow for base circle grind and stem height variations etc but not when you are settting up a motor with the cams you are going to run.





 

Didn't know if it was some sort of "magic" you'd figured into the equation of performance, back to the grindstone with You then, ha. Turn-Out another Beauty will ya.

slmjim+Z1BEBE wrote:

Nessism post=908255 userid=14026 I look for a used OEM shim, and only use K&L if the size isn't available otherwise.

   Weren't there other vendors selling shims too? How does one discern K&L from other vendors & OEM?  Seems too, that Mama Kaw changed their shim marking protocol some time during Z1 production.

Good Ridin'
slmjim & Z1BEBE
 

? ? ?

Would be great info for other members, too.

Good Ridin'
slmjim & Z1BEBE

slmjim+Z1BEBE wrote:

slmjim+Z1BEBE wrote:

Nessism post=908255 userid=14026 I look for a used OEM shim, and only use K&L if the size isn't available otherwise.

   Weren't there other vendors selling shims too? How does one discern K&L from other vendors & OEM?  Seems too, that Mama Kaw changed their shim marking protocol some time during Z1 production.

Good Ridin'
slmjim & Z1BEBE

 

? ? ?

Would be great info for other members, too.

Good Ridin'
slmjim & Z1BEBE

I have no idea how many different companies made/make shims.  The K&L shims that Z1 Enterprises sells have a dull appearance, and typically show less usage than a recycled OEM shim.  The lettering is also different.

slmjim+Z1BEBE wrote:

slmjim+Z1BEBE wrote:

Nessism post=908255 userid=14026 I look for a used OEM shim, and only use K&L if the size isn't available otherwise.

   Weren't there other vendors selling shims too? 

Good Ridin'
slmjim & Z1BEBE

 

? ? ?

Would be great info for other members, too.

Good Ridin'
slmjim & Z1BEBE

Some Ferrari engines (288 GTO etc) use 29mm shims.
They range from 250 up to 490 so i'd say that's a source for quality shims.
It would be nice to know if the buckets were the same dia as the Kaws too as they have a deeper shim recess which could open up the scope for some interesting possibilities.
 

I have contacted ACE, the valve height tool is no longer available for KZ900. 

asphalt900 wrote:

Cool stuff ZED! I mentioned bringing cams and ALL the bits because he said of taking it to a Harley fella, they surely wouldn't be familiar with this design and the fractional "tipping" required. I always do my own final clearance work here too because i can match everything according to what my shim selection contains. Question though i'm not really sure of? Why the 300 range?    

The mentioned machine shop also makes Ducati and Japanese heads too.



There is not much choice around here for Z1 specialiste ! 
 

zed1015 wrote:

Some Ferrari engines (288 GTO etc) use 29mm shims.

They range from 250 up to 490 so i'd say that's a source for quality shims.
It would be nice to know if the buckets were the same dia as the Kaws too as they have a deeper shim recess which could open up the scope for some interesting possibilities.

 

That's about as wildly exotic as it gets, I bet those prices would make your eyes bleed !!!!